Ya, I'd level as 5x I think but PvP with 4x+healer. A friend of mine who is in a top rated PvE guild says he believes Blood DK will be THE tank in Cata for the foreseeable future as well. Which sort of runs against the grain of what I have heard. If you ran a 5xdk for pve would you stick to all blood? Or would you mix it up?

How would this compare to a paladin team do you think? That is my other potential group. I could end up with a 2700 rated paladin as my backup for arenas.