microsoft line up isn't bad, but personally I own PS3 and not bad PC. Then Mass Effect coming to PC (better and cheaper version), there is big propability that Alan Wake is only temporary exclusive and will come to PC after about 6 months, Splinter Cell: Conviction - is coming to PC aswell (ofcourse cheaper and better).
What left: crackdown 2, maybe Fable III (end of the year) and Halo: Reach (same) - its much to less to buy X360 this year - maybe next year will be better :)
PS. Specially I didn't write about crappy titles like Ninty Nine Nights 2 etc. (there is something else?) - its not even worth to mention about it.