If you like Pokémon, I'd recommend Pokemon Unbound, its a ROM hack of Firered and has so much more content than any other Pokemon game I've ever played
For the PS1, Crash Bandicoot and Ratchet and Clank would be my top picks
For NDS, I loved the Professor Layton games.
Other than that, I haven't really played much on the other consoles so I'd love to see others recs for them