Go with the 360, but DO NOT BUY IT until after the new Falcon chipset is released, otherwise the thing will break down.
Oh, and for Gears of War fans...you just got fu*ked up the ass. Exclusively from AMN...
http://360.advancedmn.com/article.php?artid=10855
All the new Gears content isn't coming to Xbox 360. PC exclusive. Those mother****ers. Those MOTHER****ERS.