Start running 4 DK's (Frost Spec) + Druid for PvP

This has worked really well so far.

For PvE instances i absolutely tear up the mobs. All toons are level 65 now and im able to take 4-5 mobs at a time in ranges 67-69 elites.
I did follow Mosg2's DK manifesto and Ualaa write up as well. I had to modify the macros a bit to the spells i have at this level and have tested it extensively.

I found that putting spells into the wow macro helper dropped my DPS output, so i went with the ( Do Mapped Key Action ) and stepped thru them like Ualaa's setup. It keeps the runes on constant cooldown and runic power burned up.

For PvE i kill stuff so fast ive had to move onto Northrend (Howling Fjord) to kill the constant waves of spawns there (level 67 elites). The healer has no problem keeping up with damage.

I lead the DK pack with the druid and use a Grid + Clique setup for doing heals. Grid has a custom layout addon, and for PvP it shows only your own group.