If you own a DS and don't have pokemon Diamond or Pearl, you're being ridiculous.
As far as consoles go, this is the way I always veiwed it, but I didn't really invest too much (any) research into it.
The PS3 is supirior graphically, at least I assumed it was, right? It's also pretty pricey.
The 360 has more games I'm interested in, and live is cool mostly when I'm able to connect to other people.
The Wii is super fun for me to play with friends and stuff, and I might eventually buy it just because of that, and Brawl, but there are very few games that I would want to play using the wii-mote, and the games that I would want to use the wii-mote I think are the most fun as party games, and I couldn't picture myself playing them by myself.
So I bought a 360 and have been satisfied.