First thing's first; guys if you have been playing WoW for any length of time then this article will be of very little use to you as you will already know how glyphs work and what Mage glyphs there are. You probably already have them. Again this is just an update of my previous glyph article and is designed for new players or those who perhaps want more information on the types of glyphs available for Mages.
This said the next article I'm looking to throw up here will be Arcane Mages for PvE so stay tuned :)
The Glyph System
The glyphs available to your character now fall into three categories that can be best described as this:
Prime: These are the uber glyphs, they will directly improve damage (or healing, if you're into that kind of thing) output. Alternatively they may grant an additional ability to a spell.
Major: These feature spell changes but are usually only a slight improvement when compared to Prime Glyphs. Some will result in a 'trade off' eg. greater direct damage for the removal of a DoT. Other examples include increasing the utility of a spell such granting Blink an extra 5 yards.
Minor: These are either cosmetic or give some form of convenience such as removing the need for a spell's regent or reducing mana cost.
Once you learn a glyph you learn it forever (a bit like learning a recipe for your professions); this is to allow you again more versatility so you can adapt to different situations. The only proviso is that now you must buy Dust of Disappearance for 10g (reduced by faction reputation) to remove one of your Prime Glyphs so you can replace it with a new one. For lesser glyphs the Vanishing Powder is used. The video below is slightlu outdated but does explain it quite nicely.
OK everyone very clear on all this so far? Good.
So let's try and work this through by spec for the prime and major glyphs for each spec. That is not to say that if you're a Fire mage you can't glyph Mage Armour, if you're having DPM issues you should absolutely glyph Mage Armour - it's just easier for reference purposes. I'll leave minor glyphs til the end cos they're mostly cosmetic.
Remember, this is not a guide to the best glyphs for each spec (although I'll make brief comment) as I will do spec builds when I cover the Arcane, Fire and Frost trees separately. This is just an overview so that you have a reference of what all the glyphs do.
PRIME FIRE GLYPHS
Glyph of Fireball: Increases crit chance for your FB for a good solid 5%. I see no reason why you would not take this glyph as a Fire Mage unless you were already carrying some serious crit in your gear. Crit for fire mages equals more hot streaks, more hot streaks equals bigger numbers and more critical mass without casting scorch.
Glyph of Frostfire: A nice increase to damage (15%) and a 3% increase to the DoT, but removes the movement impairment. Again another nice glyph, a good standard damage increase. Often taken by Frost Mages to increase damage from Brain Freeze procs.
Glyph of Pyroblast!: Another nice 5% increase to crit chance, this time to the Pyroblast! spell. Why would any Fire Mage not take this?
Glyph of Molten Armour: Because armour actually has a 'U' in it and I refuse to spell it as armor despite Blizzard's best attempt to corrupt the English language. *Ahem* it gives a nice additional 2% to your Molten Armour spell, so with Molten Armour you'll have a nice 5% crit increase across the board. A very useful glyph but a lot of this is going to depend on your Mana. PvE Frost Mages will often take it as they have very few mana issues, Fire Mages will also often take this particular now that new gear means that they have much larger mana pools so there is less need for glyphed Mage Arnour (see below).
Glyph of Living Bomb: Again, this is a nice flat out damage increase of 3%. If you're already maxing out crit you might want to consider swapping the Molten Armour or Fireball glyphs for this one instead - particularly if you're good with the whole Living Bomb thing. I know some from Fire Mages who swear by this as it is a reliable flat out damage increase as opposed increased percentage; theorictically Molten Armour is better for overall DPS increase but theory doesn't always relate into practice when Random Number Generators (RNG) are involved.
MAJOR FIRE GLYPHS
To be perfectly honestly, I'm not very enamored with the fire glyphs at Major level; in raid scenarios I don't really see me using either of these spells regularly. There are some boss mechanics with adds that makes the Blast Wave glyph more attractive and Dragon's Breath in case things go wrong when levelling. I would be much more likely use glyphs of Evocation, Blink and Mana Shield or Polymorph at the major glyph level. Again that's just me and my play style; your may very well be different and I encourage you to explore that and experiment with these glyphs.
Glyph of Blast Wave: Increases the duration of Blast Wave's slowing effect by 1 second.
Glyph of Dragon's Breath: Reduces the CD of your Dragon's Breath spell by 3 seconds.
PRIME FROST GLYPHS
Glyph of Cone of Cold: Increases the damage of your Cone of Cold spell by 25%. A good solid damage increase but Cone of Cold tends to be a very situational spell usually used in levelling or PvP. Don't see too many applications for it in a raid environment.
Glyph of Deep Freeze: A slight change from its original incarnation, this glyph allows Deep Freeze to do an extra 20% damage against mobs that are immune to freeze mechanics (ie Bosses/large elites). Vital for end game Frost Mage raiding.
Glyph of Ice Lance: A great glyph as it increases the damage of your Ice Lance spell by 5%. A lot of raiders will, however, replace this glyph with the Glyph of Frostfire because it provides a better damage increase.
Glyph of Frostbolt: This increase the critical strike chance of your Frostbolt. As Frostbolt is the main spell you'll be casting as a Frost Mage at end game raiding the extra 5% crit is typically valued over the damage increase of Ice Lance.
MAJOR FROST GLYPHS
Glyph of Frost Nova: Allows mobs to take 20% more damage before breaking Frost Nova. I see this primarily being a glyph used in some good old fashioned frost grinding. Frost Nova, Cone of Cold, Blizzard - rinse and repeat and this glyph looks like it could serve this purpose very well. It also has some practical use in PvP and some (but limited considering the amount of damage usually dished out) use with adds in boss fights
Glyph of Ice Barrier: Allows Ice Barrier to absorb 30% more damage. Another nice damage mitigation spell and I can see many potential uses for this glyph for the aspiring Frost Mage. The glyph is often favoured by both raiding Frost Mages and PvP Frost Mages.
Glyph of Ice Block: Rests the cooldown on Frost Nova everytime you cast Ice Block. I don't know, seems a very situational use glyph to me and probably far more use during the levelling grind than in any raid circumstance - unless the MT has just made an horrendous trash pull but even then if things are going that badly wrong I don't think Ice Block and Frost Nova is going to solve your problems. I suppose it may have its uses in PvP but (although Diminishing Returns cuts that useful down) it's never been one that I have favoured.
Glyph of Icy Veins: Removes all movement impairment and cast time slowing effects when Icy Veins is cast. A very practical glyph that is perfect for when you decide it's time to hit the Nuke Button - after all you don't want the DPS increase from the Nuke to be slowed by debuffs. It also has use in PvP to assit in escaping melee classes. That said its not very popular in either PvP or PvE as there are typically better options out there. More of a playstyle choice I think.
Glyph of Frost Armour: This was added in Patch 4.1 (I believe to help Frost Mages with Mana issues in PvP, which is when Frost Armour is typically used). This allows you to regenerate 2% of your maximum mana every five seconds when Frost Armour is active. Since its introduction you get to see this being used a lot amongst Frost Mage PvP'ers.
PRIME ARCANE GLYPHS
Glyph of Arcane Barrage: Increases the spell damage of your Arcane Barrage by 4%. A nice basic damage increase, but as Arcane Barrage is the least used spell for raiding Arcane Mages this glyph is rarely used.
Glyph of Arcane Blast: Increases the spell damage of your Arcane Blast by 3%. You are going to want this as an Arcane Mage - it is probably one of the few time I will same that really this is not a choice, it's compulsory. Arcane Blast is going to be your main spam so to ramp up the DPS you are seriously going to want this glyph.
Glyph of Arcane Missiles: Increases the critical strike chance of your Arcane Missiles by 5%. I would say that most Arcane mages are going to take this glyph over the Glyph of Arcane Barrage because by and large you'll more likely be using AM more frequently than ABarr - although you may have different ideas depending on your own personal style of play. The ABarr is a nice base damage increase which is more consistent than a 5% crit increase but personally I'd still go with the missiles.
Glyph of Mage Armour: Your Mage Armour generates 20% more mana. Again I would say that this is not an optional choice as an Arcane Mage, in fact there are a number of Fire Mages who take this over the Glyph of Molten Armour. With the Mana Adept ability, and the fact that at full spam Arcane Mages eat their mana in one mouthful, you are going to want anything that is going to increase mana regeneration. If you don't take this, you're far more likely to start out well and then end up petering out about 10 - 15 seconds into a boss fight because you're struggling with mana issues.
MAJOR ARCANE GLYPHS
Glyph of Arcane Power: Whilst Arcane Power is active, the CD of your Blink, Mana Shield and Mirror Image is reduced to zero. This is quite a nice little addition, especially in PvP, that is likely to help you in certain movement fights, and anything that reduces the CD on Mirror Image is a boon in my book, I love that spell.
Glyph of Blink: Increases the distance you travel with Blink by 5 yards. Another good manueverability spell that is definetely useful in those awkward movement boss fights as well as fight in the arena when you're looking to escape a Warrior's Charge ability for example.
Glyph of Evocation: Possibly one of my most favourite glyphs of all time for both PvE and PVP. OK in WoTLK it wasn't used much for PvE because it took a slot away from a DPS glyph and healers could keep us alive anyhow but in PvP it really was invaluable. Now in Cataclysm PvE, us mages are going to have to keep ourselves alive a lot more. Blizzard have recognised this and made Evocation a Major Glyph, meaning that it doesn't take away from our DPS ownage potential. I have used this glyph on any spec I have made, it's just too useful not to include.
Glyph of Invisibility: Increases your movement speed by 40% whilst invisible. Not much to say about this, probably more useful in a PvP situation to be honest, or running away when the tank makes a bad pull :P
Glyph of Mana Shield: Reduces the CD on your Mana Shield by 2 seconds. I'm kinda meh on this, I've not had many situations where I've been that desperate for Mana Shield to be back up quickly although again maybe Cataclysm is different. If I was really that desperate for survivability I'd probably go Frost as it's still got great survivability (Ice Barrier etc) and is now a viable PvE spec. Possibly has more use in Pv but I think there are other glyphs that give you far greater utility from your abilities in PvP.
Glyph of Polymorph: I've always liked this glyph, it removes all DoTs on the target when you cast Polymorph, thereby keeping the spell intact. Useful for when someone cocks up and either DoTs the CC target or if the tank loses aggro and an irate and DoTted mob starts running towards the healer (or you). A lot of PvP'ers seem to take this glyph if they're partnered with Warlocks, Shadow Priests, Warriors, Rogues etc etc.
Glyph of Slow: Increases the range of your Slow spell by 5 yards. Again I'm kind of meh, quite likely you'll have specced into Arcane Blast also applying slow and I honestly don't know how that spec and this glyph would mesh in a PvE environment - not particularly well in my estimations. Again possibly more useful in a PvP situation as it would perhaps allow a quick cast on a focused target but honestly I don't see many Arcane Mages taking it. Again, there are far more useful glyphs out there.
THE MINOR LEAGUES
I don't have much to say about the minor glyphs, they are mostly cosmetic so really that's not a lot of point commenting; although I do like the Glyph of Mirror Image just because it looks better if your clones are casting spells in line with your spec and the Glyph of the Penguin for my Frost spec just because 'it goes together'.
Glyph of Arcane Brilliance: Reduces the mana cost of your Arcane Brilliance spell by 50%.
Glyph of Armours: Increases the duration of all armour spells by 30 minutes bringing them to an hour, the same as Brillance. Makes life a little easier for managing buffs.
Glyph of Conjuring: Reduces the mana cost of all conjuring spells (Conjure Food, Conjure Water etc) by 50%.
Glyph of Mirror Image: Your mirror images cast Arcane Blast or Fireball instead of Frostbolt, depending on your Primary Talent Tree. As far as I am aware this is a purely cosmetic change.
Glyph of Slow Fall: Your Slow Fall spell no longer requires the Light Feather reagent. I use this a lot because anything that saves on bag space is useful to me.
Glyphs of Polymorph Monkey/Penguin: Your Polymorph Sheep spell turn the target into a Monkey (or Penguin depending on which glyph you're using) instead of a sheep.