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. (more…)