Honestly, I already have.
the only SNES games I still own are clock tower and the mario all-stars & world cart.
I don't really miss any of the games I sold off last year, and if I did, I sure as hell wouldn't be paying what the snerds want for them.
PCE
Bonk, Ys1/2/3, gate of thunder, rayxanber, VALIS.... come on
Genesis
Rocket Knight Adventures, Gunstar Heroes, Sonic 1/2/3/knuckles, road rash, shinobi...
as for the Neo, it's really a great system, but I find myself playing about 6 games, and that's kind of it.
great games though they may be, I just don't see them lasting me forever.