Most 5th gen games are now unplayable to me. IMO the NES has aged much better the either the N64 or the PS1. Snes has aged by far the best.
I think the 6th gen will age much better, as shown really by the Wii, I think the 6th gen reach a plateua where any better is a luxory, not a nessecity.
End of 2009 Predictions (Set, January 1st 2009)
Wii- 72 million 3rd Year Peak, better slate of releases
360- 37 million Should trend down slightly after 3rd year peak
PS3- 29 million Sales should pick up next year, 3rd year peak and price cut