The 369, huh? It's basically your preference. The 360 has much better graphics (and Halo 3 is in the future!!), but the Wii is just tons of fun. If you're a hardcore gamer, and you like shooters like Halo, I'd go for the 360, but if you're more into just having fun, I'd go for the Wii.
I got the 360 today for Christmas, and it's pretty sweet. The only warning I have is that it would be pretty dumb if you're not willing to pay for Xbox Live.