Monkey Island games
The PC version's only saving grace was that it came on CD rather than 4 or 11 disks (it might have come on 4 or 11 disks initially though).
Otherwise the graphics suck, they're horribly blocky (good ol' VGA), and the usual rigmarole of getting DOS sound support ensues unless you happen to like the PC speaker :-)
UFO Enemy Unknown sucked on the Amiga. Memory leaks, lack of colours, and it really wasn't meant to run on stock Amigas... the music is quite nice though :-) Admittedly I play the AGA Amiga version under emulation because I can't play the PC version for two reasons: One, Windows 2000, and two, even if you run it in DOS, on a 1.5GHz processor it goes
a little too fast :-)