Haha, remake Commander Keen.
I'd personally like to see Wing Commander 1 & 2 remade. I had the second one on a 5" floppy disk from about 1992, but alas, it went missing when someone tried to put it on 3.5" disks because they stopped making the 5's.
What else? A decent remake of the old Network Q RAC Rally game from around 1997. The one with Ford Proton Wira, Ford Escort and the old Subaru. I loved the music in that game, aswell as the novelty of changing around the with the set up of a car before a race, then fixing whatever was wrong after it. You could make out on the night stages that the headlamps had been smashed if you hit a wall or rock.
Would also be nice to see LBA 1 & 2 without those awful isometric viewpoints.
MechWarrior 2 is another one that could do with a little cosmetic makeover, too.