I love the good old fashioned style platformer. Especially ones that follow the Mario 64 route - there are X number of Y in the level, go through a bunch of challenges to get them all. Love 'em. Seem to be hard to track down these days, but if you're willing to look hard enough, you can find a fair few, mostly on the PS2.
Games like that include the other 3D Super Mario games (obviously), the original Jak and Daxter, Vexx, Looney Tunes: Back in Action, Pac-Man World (to a degree), Rayman 2 (or Revolution, it's an excellent remake), both Wallace & Gromit games, the Tak series and about 80% of animated film tie-ins. Ratatouille was a good example of this.
I'd recommend Jak & Daxter, Vexx and the Tak series. Shouldn't be too expensive these days.