All puns aside, I did some reading the other day and the consensus amung the PvPers is that the most OP / Braindead Melee spec to play is 2H Frost DK. So I popped on my DK, dropped my Unholy spec, and went Frost. The results were amazing.
If you are looking to casually PvP right now and enjoy Melee, then Frost DK is the way to go. You have an AoE CC, can break almost all forms of CC naturally, have a steroid, decent defensive CD's via healing, and can pump out sick damage whether the enemy is high or low armor.
I was raving to Gellin about it last night and he asked about 2H vs. DW, and for PvP you DO NOT want to DW. DWing requires an extra 6 talents that are better spent in the Blood/Unholy trees.