Ugh, that's hard. Really hard.
XBox 360 certainly has the best games collection currently out there, and XBox Live would be awesome if I'm not paying for it

. I'm assuming I get the WiFi adapter free.
The Wii'll have the most stuff that interests me by the end of the year (Smash Bros Brawl!!!).
The PS3 is definitely the best hardware and can do the most interesting things (come on, LINUX! And Home and EyeToy-based games). But I really don't see much in the
immediate future that interests me. However, wherever Burnout Paradise and Kingdom Hearts 3 end up will make a HUGE difference in my decision. If PS3 got those two games, XBox 360 would drop off my consideration list.
With what we know right now? Wii. Realistically, I'd want Wii and one of the other two (my opinion is right on the edge, I see a ton of promise in the PS3, but the 360 has already delivered). Of course if price was not an issue at all I'd have all three
Of course, right now all I own is a Wii because it has the games I'm interested in (Smash Bros, Mario, Metroid, Zelda) and I refuse to pay over $300 for a console.