I have an Xbox 360, and I really like it. I'm not much of a gamer at all (right now the only 360 game I play is Guitar Hero 2), but I like the console. Its graphics are pretty good, even IMO comparable to the PS3, though not quite as good. The profiles and achievements are cool, and of course now most games are on Xbox LIVE and if you know someone who has a 360 you can play a variety of different games with them. Then it's a link to your media center if you have one, so you can use it with your computer to rent movies, look at photos, play music, etc...
I probably wouldn't have paid $400 for it, just because I'm not such a gamer. I got mine from one of those "free" sites... it ended up costing $16 and taking 4 months to complete, but I'm glad to have a 360 now!
I do really want a Wii, and I am doing a free site for it too. The issue is the company can't find any Wii's, so I will need to find one myself. That's going to be hard to do
I think the Wii appeals to me because it's something different from pushing buttons. It looks like you actually get into the game a little more than usual. Even if it's just for Wii Sports, I really want one!