Oh bloody hell, everyone. Ninja'd on pretty much all of my suggestions.
-Okami
-Rayman Origins (legends too when it comes out. Come on, how can they fuck up a follow-up to Origins?)
-Sly Cooper (1-4. 4th game made by other people, but don't let that deter you)
-Ratchet and Clank (1-3, Deadocked was ok but lacked colour compared to the other game, and the 3 Future games)
-Jak and Daxter (1, and while 2-3 lack the lush colours, hold your judgement until you see Haven Forest in HD)
-Beyond Good and Evil
-Mario Galaxy
-Jet Set Radio
-Journey
-Bastion
-Spyro 1-3
-Crash 1-3 (not a fan of the first one, but it's not BAD)
-Banjo Kazooie/Tooie
-Sonic Colours/Generations
-Klonoa (original first game is on PS1 and ported to Wii. Second game is on PS2. Very cutesy and easy, but fun)
-Legend of Zelda: Wind Waker (being ported to Wii U too, though I guess most Zelda games are colourful and epic)
So ya, most platformers out there fit the bill of "coloruful" and "epic". Personally, I think Ratchet and Clank Future: A Crack in Time is among the best looking games this generation. So much colour and detail!
I would suggest Conker's Bad Fur Day, but physical N64 copies are hard to come buy (and don't come cheap) unless you buy the not as nice looking Xbox port.