I'm running 2x HPally, 6x Unholy DK and 2x Mist Monk.

I'm very low ilvl - like 305 but it takes a group, even at ilvl 360 to take me out (I hang around in wPvP haunts so mainly geared players). I'm happy with that and think when I get to 340+ I'll be in a really really good place.

If I had the choice, I'd remove the Monks for DK as they don't work as well as they used to.

Unholy DK is amazing. No follow problems with IWT spam and their ranged damage is enough to take anybody out. They also have very high AoE over spill so amazing for wPvP group fights.