I can think quite a few games but here's some games in particular that I'd love to see remade:
Blaster Master (NES)
The original one. Man, I still love this game. I only beat it once with a Game Genie and once without, but its replay value is just great. Control-wise, I would assume it would be better off on the PSP than the DS, although I can't really say anything because I don't own either of them. XD
Castlevania II: Simon's Quest (NES)
I watched an Angry Nintendo Nerd clip about this game and I can understand why a lot of people would be frustrated with it, but honestly, if they could redo this visually and make the day/night transitions smoother, I would be quite pleased. It was one of the rare Castlevania games where Dracula's Castle wasn't the entire level (although Symphony of the Night was still the best, in my opinion).
Crystalis (NES)
I'd really like to see this game remade. The Gameboy Color version was actually a downgrade, which I blame entirely on the completely different music.
Super Mario RPG: Legend of the Seven Stars (SNES)
I would have no problem with them keeping the visuals in this game. I'm sure they could come up with some nifty features if they could adapt it to the Nintendo DS.
Zelda II: Link's Awakening (NES)
I heard rumor a while back of a remake but I doubt it, especially since this game wasn't liked nearly as much as the others. This game has excellent replay value for me and I'd love to see it visually remastered.
Lunar Silver Star Story: Complete and Eternal Blue: Complete (Playstation)
Considering the "Complete" versions were remakes in themselves, it would be nice if they at least re-released them on PSP or something. There's a few copies of the first one out there but that's it and without the cloth map and hardback manual, it's still $50+ USD on E-Bay...with good reason. There's always Lunar Legend, I suppose, but it just wasn't the same.