I am usually screwing around in MW2 and Forza 3. My friends and I still do a Halo 3/Reach night on Wednesdays. We have a crap load of custom maps that we play around on, not really into the whole matchmaking system of that one. Tried Black Ops as well, still own it, still hate it lol. I pickup GTA IV every once in a while as well.
Looking forward to Battlefield 3 and Forza 4 when released.