SomnusSleeper wrote:
Defense rating doesn't translate directly into defense.
This.
Defense increases dodge/block/parry/uncritability, but seeing as we can't block or parry a lot of the benefit of defense is wasted. If you're needing to get uncrittable, resilience is often a faster and cheaper way to do it. The new stam/resilience head enchant from the Shattered Sun is a good option, as is the +15 res chest enchant. PvP Dragonhide bracers are also extremely good, or if you're got the arena points the S3 (and soon S4) gear is roughly T5 level+.
I strongly reccommend you visit
http://be.imba.hu/, it'll look up your character details and tell you exactly how much defense or resilience you need to be uncrittable, as well as other useful tidbits.
You can also use the following macro to check your % anticrit. If the value it gives is 2.6 or over, you're uncrittable.
/script DEFAULT_CHAT_FRAME:AddMessage(2.6-(GetCombatRatingBonus(CR_DEFENSE_SKILL)*.04+GetCombatRatingBonus(CR_CRIT_TAKEN_MELEE)),1,0.5,0)