i have a dk group at level 79, i highly recommend leveling 4 and keeping a shaman for heals

go all blood and a tiny bit of frost for annihilation and you're single target dps will be out the door nuts, plus with upcoming changes you're gonna get a ton more healing and aoe dmg will be better than it is now...

right now i run with 3 blood spec dks (with juts a bit into frost for obliterate) and a feral druid for tanking, leveling my shamans now so that i can add a shammy into the mix for totems/heals... overall i'm super impressed with this setup for melee boxing, its a TON of fun playing dk's!