Here is my Death Knight, Methusaleh. I was actually extremely happy that I was able to get the name. I wanted the name for the meaning it represented in Biblical times. (I am not going into a discussion on religion, so relax.) As far as the character goes, I just have not been able to get into the playstyle of Death Knights. To me, and I am more partial, I would prefer a retribution Paladin over the blood spec that I started with. However, I did respec to Unholy, and for some reason, I tend to like it somewhat more.
My big thought with Methusaleh was critical strike rating. I switched in any gear that provided more critical strike rating. I will admit, not too sure how it affects the numbers, but it seems to be providing solid numbers. In all honesty, I do not know if I will ever level him all the way. I definitely enjoyed the story line and that was worth the time vested in the character.
The most fun aspect of playing the Death Knight is the ability to take on mobs that were imposible on any of my other characters at that level. I like to challenge myself, but honestly, have not been able to find a challenge as the Death Knight class is truly a powerful class. I suppose when I try my hand at leveling Methusaleh again, I can always just try pulling more mobs, until I find the right mix.