I'm relatively late to the Wii console scene, so there are a lot of highly rated games that I have not played. I am currently working my way through Epic Mickey, which I bought off EBay for $6.51 shipped. The camera is problematic, as you would know from the reviews, but I still find the game remarkable for its imagination, graphics and paint/thinner mechanics. I am also going through Lego Harry Potter Years 1-4 with my daughter, also bought used at a ridiculously low price. It's an easy game with great coop play and humor. There is also a ton of stuff on the Virtual Console. There has never a better time to be a Wii owner. The games are plentiful and as fun as they were when they costed $50, but are now so much more affordable.
What are you playing now?