Oh yeah, Beyond Good and Evil is one of those must-play games regardless of platform preference — a classic that goes in the same boat as all the LucasArts classics, Psychonauts, etc. Also agree that Ratchet and Clank on the PS3 is definitely a superb platformer, and I'd assume its predecessors were good too although I never played them.
If you have a 360 then Rare's Banjo-Kazooie: Nuts and Bolts is well worth playing, being the second sequel to one of the finest 3D platformers ever (Nintendo 64's Banjo-Kazooie). It has a more vehicular slant than its predecessors, but is nonetheless great fun; it also does a good job of taking the piss out of itself and the platform genre in general.
Excellent production values, too.