Honestly I'd have to say nothing. I've had this conversation with friends and I've come to the conclusion that I do not want any of my favorite old classics touched up and redone. Turtles in Time came out redone and reworked and I loved that game to death, when it was on the SNES. But it hasn't stood well in the test of time and the rework it got didn't do much for it. Honestly one of the biggest things those classics have going is that I play them under "Nostalgia goggles" which ups my enjoyment tenfold, take that away and I can't have the same enjoyment. So my answer is none
banjo tooie for n64 was awesome in no other game do you transform into washing machine that fires underwear and in no other game can you fall asleep on whim to gain health
I'd say probably Sonic and Mario. Wait, they already did that? Oh wait those sucked. So I'll restate it. A Sonic/ Mario game THAT WAS WORTH A CRAP. If they could somehow manage that, I would get it. Maybe they should have just stuck with 2d. Anybody notice that Sonic/Mario had their best ratings while 2d, and in 3d people forgot the titles' names becuase they were so crappy? I remember I had to get the Sonic Arcade game for the PS2 just to remember that there were 3 Sonic games that were racing on the SNES. heh heh....
Oh yeah, I forgot something (I didn't see an edit button on there). Lunar. They re-did it once for the PS1, but I think they should do it again. Too bad that'll never happen. The company went bankrupt with Lunar 3...