We have a Wii and I love it! I would die for a Wii Fit though.
Nowhere around here has even been getting any in lately.
To be honest, my favorite game is Wii Sports. Personally, I love action type games where I can get up off my butt and actually participate in the game.
My fiance has a racing game that he likes to play...I can't think of the name of it at the moment. We bought a steering wheel that you can clamp down to a table but he doesn't really like using it. To me, it's just as easy to "steer" with the wii remote. You might consider a handheld wheel but you don't need it.
Our Wii came from ebay but I've purchased all of the games and accessories from Gamestop.
I forgot to add- If your Wii didn't come with a wireless sensor bar, get one of the those so you don't have to have your remotes plugged in to play. Also, consider getting nunchunks for each one of your remotes because quite a few games do require these. A charger for the remotes is also handy so you don't have to worry about changing batteries.