IMO, PC for all my hardcore gaming habits, and wii for everything else. I had a 360 and I'm kind of glad my brother took it when he moved out because I would've ended up wasting more money on it. I'd buy a game that looked good and then realize that it just doesn't appeal to me that much. COD4 was good but better on pc. Halo 3 was an ok party game but nothing special (wii has way better party games). Mass effect got old fast on 360, but I downloaded it on pc and enjoyed it. A lot of the best 360 games I could have just gotten for free on pc actually. GTA4 was good but still just another GTA. Fable 2 was a good renter.
That's another thing, games lately are just so short and don't have much replay value. I can fire up the classic consoles any time and they're just as fun as they were back in the day. New generation shit is mostly flashy.
Overall I was disappointed in my 360. My wii is a lot of fun though. Games are cheaper too, especially on ebay. I'm really glad I made the switch. It's got a few good games for the "serious" gaming or whatever, mainly the rpgs imo, and then it's got a bunch of just fun games you can pop in whenever and have a good time. And a lot of the best high-rated games are somewhat "unpopular" and lower in price, like I just picked up Battalion Wars 2 for $14 and it's a good time.