The other thing I got for christmas that is taking up time is this one.
Absolutely brilliant. Definitely the best first-person shooter of the last few years - single player anyhow. Haven't had a chance to play the deathmatch yet. Basically does everything the first one does, but better. That includes making me think every few minutes "wow, this is awesome".
The facial animations and the realism of the buildings and terrain are really what makes this game work. It's really astonishing - I have long wondered when we're going to get to the point where computer games are like the holodeck on Star Trek, and this one makes me think that it is now on the horizon, rather than 'in a few decades'.
Also, the puzzles that use the physics engine are cool.