I have a PS3, and for me its a glorified Blu-Ray, DVD, and DivX player.  I can't remember the last time I played a game on it, and in fact I regret buying the few that I have (other than Guitar Hero, which I'd keep, even if I haven't played it in a long long time).  I do think the PS3 is worth it just as a Blu-Ray player though.  I in no way regret buying the system (as opposed to the games).
If you're a fairly serious console gamer, the 360 is the way to go.  I'm not but I know a lot of people who are.  Everyone I know that has a Wii says that it gets old real fast (except for GH as previously stated).
As for Windows 7... like Vista I'm in wait-and-see mode.  Having skipped Vista entirely I'm probably more likely to give Windows 7 a chance.  But not if my ability to run my favorite apps is gone or diminished.