Anything from the previous generation would be good, since you've got a good variety and can score stuff new and used for cheap. Anything portable would be good as well, since those can be moved around and generally are cheaper overall.
It depends on what games he likes (or, in this case, MIGHT like, since you might not have much to go on), and then going from there, but the PS2/Gamecube/Xbox will most likely all have titles that would cover whatever games he might like. So really it comes down to playing what might be considered the "best" games from last generation. Given that this newcomer might not be that great of a gamer, starting them off with easier games/genres might be the way to go.
If you went with a portable, either the DS or PSP would be more than fine. I take it by "console" you are aiming for something more in the "hooks up to a TV" arena though.
I wouldn't really know what sort of games to suggest, but here's a few anyway:
PS2: Ratchet and Clank series, God of War, Ico/Shadow of the Colossus, Katamari Damacy/We Love Katamari, Okami, any of the smattering of RPGs, Metal Gear Solid Essentials Pack
Gamecube: Super Mario Sunshine, Pikmin, Luigi's Mansion, Smash Bros Melee, Resident Evil 4, Zelda: Wind Waker, Zelda: Twilight Princess, Metroid Prime, Paper Mario: The Thousand Year Door
Xbox: Prince of Persia series, Halo, any EA Sports games
DS: New Super Mario Bros... really just check out
this thread
PSP: Crush, Final Fantasy: Crisis Core, Gurumin, Lumines
I mean really you could go back further to the NES/SNES and potentially the Genesis, but that might be pushing it. Plus that stuff would be more difficult to track down. I mean hell, I'd be making people play Earthbound (as suggested by your name), but that's a little more difficult to push on people.
Hope this helps.