I (worryingly) had withdrawal syptoms from my Wii today. A whole day at work and all I wanted to do was hit some home runs and blow up some tanks etc.
Never felt like that about games before. I see quite a few articles have already cropped up about possible longevity, for single player gaming they may have a point, but I've managed 7 or 8 hours alone on Wii Sports already (pesky training mode) on top of the 3+ hours in multiplayer mode, which is more than I played a lot of my PS2 games full stop!
Oh and Monkey Ball is shite, by the way. Just incase anyone is considering it, better off with Rayman.