He's played more recent than the PSX, one of the earliest episodes involved playing Steel Battalion.
That was more of a one off thing, really...
But yeah, I do wish he'd move onto more 16 and 32 bit stuff. I'd love to see him handle X4, 5, 6, Legends, Legends 2.
Oh and just to be a bastard, Beyond The Beyond. Not because it's a terrible game, but because the boredom would be crushing. >:)