Death Knights are exceptionally easy to play.
They're, in my opinion, a lot more fun than most classes as you are setting yourself up for combos and what not depending on how your runes are stacking.
I used to play as Unholy, which is a fun way to level and the way I leveled my first Death Knight to 70.
I then tried Blood spec and simply, wow! If played correctly, you can stack up your death runes to give you 16 Heart Strikes in a row. 8 seconds of spamming your hardest hitting (as blood spec) move.
Bring on 3.0.1! More dps for the bloodies