I'd say Paper Mario is probably the best looking game on the system. It's a shame it came out so late in the N64's life and didn't get the attention it deserved then. Great game, far better than Mario RPG on the SNES or Mario & Luigi on the GBA.

I'm going to have to pick up Paper Mario 2 here soon before the Gamecube tanks any further and places quit selling Gamecube software.