Crackdown, it's one of those games you play when you just feel like being unstoppable and kicking some ass.
Dead Rising is amazing. uhh Frontline Fuels of War will be cool. NCAA March Madness 08 will be good. MX Vs. ATV untamed is pretty awesome.
essentials: halo3 (awesome multiplayer) call of duty4 (pretty good multiplayer and just awesome game in general - graphics, authenticity, etc.) bioshock (game of the year - kinda self-explanatory) really really good games gears of war (innovative game) eternal sonata (best rpg for 360 so far) guitar hero 3 or rock band
GET WARHAWK TODAY! H.D. quality, good picture, sound! all you need now is an 50 inch T.V. and a bag of popcorn. Its pretty amazing.