I personally have a 360 and a wii

360 - Good graphics, the graphics on the 360 are excellent, matched only by the ps3. theres the xbox live arcade - where you can get games like: pacman, alien hominid, tetris ect, theres also such a wide vareity of games, including xbox only games like Halo3 and many of the games coming out on ps3 are also coming out for the 360 aswel.

wii - The wii has decent graphics.. typical nintendo graphics - cartooney style. many games are out for that, some are shooting (red steel) and some are fun games where everyone can join in eg: tetris. The wii consists of mainly "childish" games, whereas the xbox targets older people with their graphics and gameplay, wii also has the mario series and all the retro games downloadable from their database which consists of, old mario, zelda ect

overall i think if your a hardcore gamer who likes a bit of fun and a challenge of skill - go for the 360, the wii on the other hand.. if you like cartoon style games and would prefer to have the whole family playing without the need to remove small children from the game - go with the wii

Summary for 360 - Hardcore gamer, good graphics, more "grown up" games
Summary for Wii - Child?, Family, and the main aspect F U N!

But its totally your choice