I consider the wii to be a social gaming apparatus. If you spend most of your time on your own or with just two people, I wouldn't bother. If you regularly have friends over, then yes.
Yes it's fun at first, but in the end all the games aren't about the game, they're about using the remote.
Sold mine almost immediately after buying it. Big plus was that you can play NES and SNES Mario using Wii points. That was fun.