I visited a friends house a few weeks back and was amazed at how cool Wii is. I like the fact that they have worked on a new concept rather than trying to take on Sony and Microsoft. I too had aches and pains the next day, but also had the most fun I had had in ages. Tennis is great and I wasn't too bad at boxing either.
I own a PS2 and while I do enjoy the odd game to relax with, I don't generally play an awful lot. I am honestly considering investing in a Wii though, as it is such fun and appeals to people who normally would not be playing on a games console.
Well done Nintendo!!!!