as a rule, you should find no more than 3 or 4 stats that you find useful (2 or 3 is better, i say), choose these stats considering your main role in instances, questing/grinding/farming, or pvp'ing. like if you were a shadow priest, i would recommend
spell dmg,
spell hit,
and mana regen (X mana every 5 sec.).
then maybe, stam, int, spirit, or maybe spell crit (...for every 5.5 secs you can even cast a spell that crits at best).
then once you find your 3 or 4, whore yourself out only for gear that at least has two of those stats. something with stam and agi needs to be booted and replaced with an outlands green that has your stats. buy them from AH if you have to. "of the elder" or "sorcerer" gear isn't bad, even though i don't like gearing for stamina, unless it's for pvp. but even then..
and don't be one of those guys that wears something with wrong stats simply because it's blue...or even purple. the old dogs inspect your gear and will label you a fool. aim for the stats you want and let them add up. that's where your power comes from. when stats are too scattered, it just makes you OK at everything, but not good at anything.
~Yin~
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"Yin's not that bad. Don't give me that look, she's not...."