I'm surprised no one's mentioned Tomba! yet.
Rediculous, colorful and fun, I think it's aged quite well over the years.
Hell, I still enjoy the look and feel of older PS1 games like Bushido Blade 1 & 2 and the Saga Frontier games (though I liked SF1 moreso than SF2). Spyro and Crash Bandicoot have aged pretty damn well imo as well (off topic: try playing Spyro or Crash Bandicoot on ePSXe with the Cartoon or Storybook filters: They look fucking AMAZING)
Thoguh I gotta say there were a fair number of games that were bum fugly even back then (I'm looking at you, Nightmare Creatures!) or had horrible, tank walking controls (basically every survival horror game).