I don't seem to be able to make my mind up about DPS specs, do I? Then again, the thing I love about Death Knights is the fact that whilst most hybrids have one or two DPS specs to pick from, we have one in each tree, each with it's own feel and each close enough to the others that you're not losing out.
Case in point, after downing Heroic Anub'Arak last night, he dropped two lovely one-handers. The Rogue didn't want them, so rather than see them sharded, I decided to go back to Frost Dual-Wield, that being my original spec when I reactivated Graysun. To be honest, I'd been getting some schtick from the meleers about me not giving them buffs ever since I went to Unholy, so this felt like I was "giving something back" (not that the lazy bastards ever gave me anything!).
I ended up going with a 0/54/17 spec that included Improved Icy Talons for the melee haste buff. I tried it out in heroics afterwards. I miss the big numbers from a 2-hander build (my best crit was something like 5k), I also miss the AP buff from Bladed Armor and the lack of threat reduction from Subtlety means I'll never pug an instance as DPS again, but it should be pretty nice for our meleers. Plus it's always nice to play with new toys!