T.F.
We've had our Wii about a year now and of ALL the things we have around here, it is the 1 thing that all of the teens keep playing. My husband and I enjoy it as well.
I have 1 daughter (13) and always alot of guests here. They are always doing something on the Wii. Wii also has a function on it which will play your Game cube games which makes our Gamecube non-existant right now and gathering dust.
The Wii games we have are the basic first package with sports. LOVE it....we play as a family and Yes you work out when you are boxing, playing baseball, tennis, golf and bowling. The other games she has a Mario games. The Guitar Hero is also a hit with the kiddos here.
If/when you buy one, get a couple extra remotes. I think we have a total of 4 wireless remotes. Boxing requires another remote of some sort so make sure you get that too. We have it in a game room on a big Dell 46" Plasma TV. Things can get wild and fun so I do have to remind the girls to watch what they are hitting. I've had one get so into her game she scraped the top of the Dell (ouch) but the screen was not touched.
The Wii Fit is on our list of things to get next but in all honesty, we've had so much fun with the sport package, I know we are keeping in shape with that too.
Enjoy