Well, like most will probably say, it's all about the games, so if you're content with what's available/to-be available on PC, you're pretty much set, long as you can live with games that will more or less ship with bugs, and as of recently, online-activation and DRM seeping into titles.
That, and the thing with the 360 is that Microsoft has released another revision of them recently, sporting an HDMI connector on standard 360 models (where-as it was previously exclusive to the more expensive 360 Elite), personally, I'd just wait it out if I were you if you were to ever take that direction.
(still waiting on the 65nm processors before purchasing one with my own cash)
That, and the thing with the 360 is that Microsoft has released another revision of them recently, sporting an HDMI connector on standard 360 models (where-as it was previously exclusive to the more expensive 360 Elite), personally, I'd just wait it out if I were you if you were to ever take that direction.
(still waiting on the 65nm processors before purchasing one with my own cash)