Sweet, I own no video game systems. I only play PC games that actually work, but I keep track of the console stuff anyway, and I love this kind of pointless debate.
At my college there are about as many Wii owners as there are Xbox 360 owners. It really depends on whether you want US made rpgs and competitive shooters (XBox 360) which does seem to make up the mainstream of college level gamers, but not completely, Japanese made rpgs or Metal Gear Solid (PS3) which is still too expensive and not worth it considering the low variety of games, or fun party games and slightly larger variety, although sometimes lower quality games (Wii).
If you limit yourself to only violent and "mature" games then you're missing out on some of the best creativity and fun in the market. So little has changed in the FPS genre since the games of Halo and its generation. So many people made fun of Windwaker when it came out for being childlike because of cel shaded graphics, but since then I've seen some pretty amazing cel shaded games such as Okami on other systems. Graphics don't determine the quality of a game. Neither does the level of violence or realism. If I want to see something realistic or violent or good graphics, I can just watch a movie or look at screen shots online. That is not to say that some shooters aren't amazing, but I think that Valve has taken a monopoly on the originality of the FPS genre with Half-Life 2, Portal, Team Fortress, etc.
Anyway, back to the subject. The only real problem with the Wii, is the lack of quality third party games. Most of the real good games on Nintendo systems have usually been published by Nintendo and developed by Nintendo or a Nintendo owned subsidiary. Some of these franchise games, such as Mario, Zelda, Metroid, and Donkey Kong, are still fun, but they also lack originality, especially in story lines. There are still more games with original and hilarious game play on the Wii then the other two systems combined. The incorporation of all that motion sensing shit helps a lot too. There you go, a short history of modern video gaming, with an emphasis on the originality of game play. Sorry for my rant.