Post by DraconisAerius
Check out this guide for the info you want.
http://www.wowhead.com/forums&topic=98519
Post by Guedhe
That guide is rather painfully out of date, being that it seems to mostly be post 4.0, but pre-cat. How you spec depends, in part, on if you are doing battlegrounds or Arena(and within arena, comp can change things a bit too). I personally found that with the rampant dispelling going on, Destro was feeling pretty gimped in both arena and BGs, so I have been running as affliction. I use this spec/glyph combo:
http://www.wowhead.com/talent#IbGrRGsGcdhbM:scMmVd0MmI have been gemming for int+haste in red/yellow sockets, and int+hit in blue, and after I got to 410hit, I've reforged everything that I could to haste. Haste is huge in PvP, because the faster you can get your fears/dots out, the better you will do. The extra damage from increased dot ticks is just icing on the cake.
There are a number of ways to get the appropriate amount of spell penetration, and I'm still not sure what the correct amount to aim for is, but I think the very base amount you want to get to is 195. I did this by putting the spell pen enchant on the bloodthirsty cape of diffusion. This is, to the best of my current understanding, total overkill, but I plan to replace it with the Vicious Cape of diffusion soon, which makes the point moot. I would suggest getting your gear in roughly this order:
1. Bloodthirsty Gladiators Medallion of Tenacity: a PvP trinket is a must, this also has a good amount of resilience on it, which helps affliction survive long enough for those dots to wear your enemy down).
2. Bloodthirsty Gladiators Drape of Diffusion (with spell penetration enchant): CCs are a game breaker, watching that RESIST pop up after you manage to get off a cast time spell (fear, haunt) is brutal, and this is that fastest, least complicated way of avoiding that.
3. Bloodthirsty Gladiators Felweave Handguards: Cheapest of the set pieces (along with shoulders), has a nice little buff to your portal, and has hit+blue socket (where you'll pick up a little more hit) getting you well on your way to getting to the hit cap.
4. Bloodthirsty Gladiators Felweave Amice: Pick this up just because it's cheap, and will get you the +400 resilience 2-piece bonus. Reforge the mastery to hit.
After that, you can really collect things in whatever order you want. I would suggest getting the +hit necklace and belt, and the +haste wrists and boots, since. Any extra hit, again, can be reforged into haste.
Hope that helps.