So, I am one of the 5 or so people who still play a warlock, and I have raided quite a bit. I raided up to BT a few times post nerf, and have run Naxx a lot lately.
Now in 3.1 I have switched to Affliction, and while my DPS is all right I am not doing as well as I was with a demo/destro combination of pre 3.1.
I am going to keep testing and playing around. Pretty soon I am going to dual spec Destro, and get a feel for both. I fell it will be stronger on the AoE, but I am not certain that will be as important in Ulduar as it was in Naxx.
Please reply with any thoughts or questions on Warlocks.