I'm going with the Wii.I played on each platform,and the Wii was the most inovative for me.Soul Calibur ftw!
I have never seen Wii, but I played on both Xbox and Playstation and will go with Playstation. It really leaved pretty good impresions.
Used the Wii and I did not like it because the motion sensor does not capture very well the movements. I haven't used XBOX 360 but I know it's games aren't in HD. I own a PS3 and it has HD, and great motion sensor with the Move controllers. Some friends that do own a 360 told me the games that are only for that machine are better than the ones that are only for PS3, but I really can't say.
PS3...Sony was always a gamer's whore ( they'd take any title that wasn't an exclusive) and besides they have the most games I really want to play, that is, the best exclusives...GoW, MGS, FF 13 versus etc
The CAVE games are what makes the XBox360 so appealing over the PS3 for me, but it obviously needs to be an imported Jap/Asian one lol. Games like BlazBlue make it to both the 360 and the PS3 but not the Wii, however the Wii does have some excellent games like Muramasa and Sin and Punishment 2.