So I'm a little confused what to do here now that DR's are in the game. It makes it much harder to try and min/max yourself. Anyway, I have seen some talk on this forum about block rating being given a lot more weight than dodge/parry since they are hit so hard by the DR. There's something I haven't seen answered really, so I'll just ask it: What is the best thing to do gearwise for living vs raid bosses?
It seems to me it would still be pertinent to continue stacking dodge/parry even if they are hit by the DR, since that will stop chains of hits. But I know you guys have tons of math on this stuff and math is something I'm terrible at, so I'm asking you, what's still best for MT'ing? Or maybe I should phrase it as "What makes you easiest to heal?"
Well for a warrior tank I'd say stack stamina, defense, and expertise and you'll be golden. And it just so happens that those stats cover your three main gem colors too. Enchant for defense first (shield, cloak, chest), and maybe expertise second (bracers, gloves), and stamina third (legs).
Get an addon that shows you the item level for each item (I use RatingBuster) -- A higher item level will almost always be better than a lower one.
Defense spreads the stats out in a balanced way automagicly. Stamina is great for EH. Expertise will boost your threat and offer good anti-parry-gibness, with the gear currently available in game you could stack exp for a long time and still not reach the parry cap.
I've cleared all the WotLK content on both 10- and 25-man raids except for Malygos (just a matter of time) and the above plan has worked out just fine for me. You shouldn't need to worry about min-maxing for anything currently in game -- the level of difficulty simply isn't there yet.
You need a pretty good health pool if you are looking for achievements (At least 27k or 28k unbuffed for those really large damage ones but higher is better). The rest of the stats you need you will get from the gear hitting that stam value. As has been said nothing is difficult enough that you have to min/max. Get a nice hit point pool and some tolerable avoidance and most things will be a total joke for your healers to keep you up through.
All min/maxing does is let you get away with fewer tanks or fewer healers which is just not needed when you can run most raids with 5-6 healers and 2 tanks without much issue.
On the other hand if you are looking to prepare for Ulduar in the long run I have set a personal goal of 31k unbuffed hps, capped expertise for dodge, and as much armor/avoidance as i can toss on top of that. Thats pretty maxed right now within a few hundred hps. You'll be looking at something like 45-50% combined dodge/parry and 1300-1500 shield block value depending on what pieces you take. If you hit that now you will get really bored with the damage you take while tanking.