Just to weigh in, I'm 34, female and not what I would consider any sort of hard core gamer... I own a SNES and a PS2 and now the wii. I bought the PS2 specifically to play Kingdom Hearts, so that tells you what sort of games I'm into.
I love the wii!! Solo games like Zelda (and I was never a huge Zelda fan) rock although I dilly dally a lot while playing them and the wii sports will suck people in who claim they don't like video games. Even us older kids.
The wii isn't that expensive, really... and personally I haven't had a single second of buyers remorse over the purchase even though I don't have time to play it every day.