I wanted to be so smart ass and say save every penny for your next PC update but that would be expected. =(
Honestly if your on the fence then don't get one, you may end up disappointing yourself.
For myself I can say Brawl got me into getting my Wii, I'd believe that most who buy a console have a line up of games they want that they knew would be there... So I guess I could post some games for you but I doubt your ignorant to the Wii line up.
Oh well here goes:
1 No More Heroes 2: The game uses the best Wii-mote controls to date for light saber play, it's got it's own sense of humor and doesn't take itself seriously. I'm expecting 2 to be more of the same and a bit more complete. Original game play would take 16 hours, but their are 3 difficulties and lots to unlock.
2. Monster Hunter Tri: If you haven't tried a MH game yet here's the down low, this game isn't (IS NOT) pokemon, the game puts you into the boots of your custom character and you complete missions, the enviornments are the killer part, the game really places you in a Swamp or a Forest and the result is you are immersed. Find your prey or complete the objective, either way this game is loads of fun. (Especially knocking your team mates around with your great sword accidentally)
3. The Conduit: I don't know, but some people like shooters a lot, their's just too much hype for this game, to be fair I can say that I personally am impressed by the visuals in motion from the recent videos I've seen, I'm not even talking about graphics though I mean how the game flows - but there's still some barrier.
4. Overlord: Wii: IF you like RTS or tried pikmin and liked it, then you will probably enjoy this title, I've played a lot of PC genre proficient games that try out consoles and fail, but Shigeru made the console formula for RTS and it works, these guys at Code Master pretty much copy pasted the goodness of pikmin and place you in the role of an evil overlord attempting to forge an evil empire, the one for the PC and PS3 were fun to me, try it out if it's your thing.
(Don't forget FFCC, it's the new FF main stream title. =P )