Spellpower is typically your strongest stat, superior to everything else, with hit a close second (until you are hitcapped). If you have higher values of spellpower and aren’t hit capped, hit is your strongest stat.
The relative worth of crit and haste depend on spec and the strength of the other two main DPS stats.
Don’t take this to mean “ignore hit rating”. Just don’t go overboard trying to get hit capped, don’t socket everything with hit, and above all, don’t let your other stats (especially spellpower) suffer just to get some hit.
You do still want to get hit capped, you just don’t want to make sacrifices to get there.
For Frostfire based specs.
Spellpower is superior to hit until roughly the 1600-1700 spellpower range. At that point, they are about even, and higher values of spellpower (1700+) result in hit being the superior stat.
Haste and crit are nearly even, though relative to the other. If you have twice as much crit rating as haste rating, then haste is more valuable. If your haste rating is twice your crit rating, then crit is more valuable.
Spellpower is generally better than, point for point, haste and crit. Both of them are roughly at 2/3 strength compared to spellpower at lower values (1200, 1400).
They become even at a very high level of stats (2600+ spellpower, with both haste and crit sporting numbers over 500). Don’t expect haste/crit to outshine spellpower until you have more than 3000 spellpower.
For Fireball based specs.
Again, spellpower is superior to hit early on. Hit breaks even and becomes the better stat at 1450+ spellpower.
Haste is always better than crit unless you have a truly skewed ratio. Even with 0 crit rating and 800 haste rating, the two stats are merely even for their point for point worth.
At low spellpower values (1200), haste is at 2/3 strength compared to spellpower, and crit is slightly better than half. As stats get higher, the gaps close.
Haste is always behind spellpower, though that gap shrinks to almost non existent at about the 2600 spellpower mark. Crit is only 10% behind haste at this point.
Again, don’t expect either of these stats to exceed spellpower until you sport more than 3000 spellpower.
For Arcane based specs.
Hit becomes even, then superior, to spellpower extremely early, by the 1200 spellpower mark.
Haste is once again at 2/3 strength of spellpower, with crit very far behind at roughly a third of spellpower’s strength, or half of haste’s.
By 2200 spellpower, haste is only slightly shy of spellpower, with crit coming at 50% in point for point worth. Haste is the superior stat by 2400 spellpower. Crit is never the superior stat.
For Frostbolt based specs.
At low spellpower values, spellpower is only superior to hit by a very small margin. They break even by about 1450, with hit being the better stat at 1500+ spellpower.
Once again, haste is at two thirds of where spellpower is, with crit hovering at merely a third of spellpower’s worth.
By 2500 spellpower, haste is just a little shy and crit is at half as good as spellpower. Haste breaks even at about the 2900 mark, and is better by the 3000 mark. Crit never gets better than 15% behind spellpower.
Don’t go overboard gemming for hit. Any more than a couple is a waste. You can pick up a great deal of hit on the gear itself.
Your helm/hat/haberdasher, whatever you wish to call it, must have a metagem socket.
The metagem socket must have a Chaotic Skyflare Diamond socketed and activated at all times. The CSD is the best metagem in the game for mages, for raiders and PvPers.
It requires that you have at least two gems that count as a blue gem. Blue, Purple, and Green gems all count. Purified Twilight Opal is an excellent choice for all mages, though you can look into the Forest Emerald collection for the other stats.
When in doubt, socket more spellpower.
Never socket only considering the socket colour. If you see a yellow socket, do not immediately assume that a yellow gem has to go there. Weigh your options, and decide if the socket bonus is worth it.
A blue socket with a socket bonus of “+5 Spirit” can be safely ignored in favour of raw spellpower. A +19 spellpower gem is far superior to a +9 spellpower, +12 stamina gem in that socket.
A red socket with a bonus of “+4 Intellect” is irrelevant. If it was a good socket bonus, you’d socket spellpower. If it was a bad socket bonus, you’d still socket spellpower. As it’s a red socket, +19 spellpower is going in there regardless of the socket bonus.
Weigh the stats you would get if you socketed according to colour versus what you would get if you socketed boatloads of spellpower. Then choose which one to go for.
Never stack spirit or mp5. It isn’t worth it.
Spirit on gear is a wash at this point; it barely matters if it’s on gear. If you have spirit, great, you get some awesome crit from Molten Armor. If you don’t have it, great, that means your item budget was spent on crit and haste instead. No real difference anymore.
Like it or not, spirit is here to stay. Just don’t go out of your way to get some.
Generally speaking, any item with mp5 on it is a healer item. If it is still technically an upgrade for you, despite the mp5, only roll for it if no healers want it.
Generally speaking, any item that has it’s budget allocated to Stamina, Intellect, Spirit, Spellpower and nothing else should be treated as a healer item. Only roll on it if it’s technically an upgrade and no one else wants it.
Try to make sure that all your main pieces (that is, your clothing, non-jewelry stuff) has at least any two of Spellpower, Hit, Crit, or Haste present on it. Typically this will be Spellpower and Something Else.
Anything with hit on it is a DPS item. The healers will (probably) not be rolling on these.
Anything with Strength, Agility, or Attack Power is not a mage item. Ignore them.
MH/OH is better than using a staff, by sheer merit that MH/OH has superior spellpower values than using a staff. Naturally, if you’re still sporting iLevel 200 MH/OH and you get a 219 staff, it’s probably better to go with the staff.
Anything else that should be included in here?