It depends if you're willing to buy into the whole control scheme etc.
The wii has some fantastic games, like Mario Kart, Metroid Prime etc. though playing on it seems a whole lot more effort than just vegging on your couch with a 360 controller.
If you're willing to pick up the controllers and wave around all day, go for it. It's a fantastic console all in, and true to Nintendo's history there's a lot of crud out there for it, but the actual Nintendo-published A-grade games are fantastic.
If you get one, get Metroid, Mario Kart, No More Heroes, Res Evil 4, House of the Dead: Overkill and The Godfather as a priority.
Really, I've been playing The Godfather recently and the motion controls are amazing - everything has been rearranged to make it feel like you're actually grabbing people by the scruff, slamming them into objects and smashing them with baseball bats etc.
Recently, my 360 has become 2nd fiddle to the Wii in terms of games, and I too allowed my Wii to gather dust for over a year (had it since launch). Only recently have I realised how wrong I was to slip into being a naysayer.