Edge on the iPhone had a great soundtrack and is definitely ripe for sampling. As for more retro stuff - hmmmm. I remember Robocop 2 on the original Gameboy (or was that Robocop 1?) had a brilliant intro tune. Aphex Twin has a fantastic track called 'Power Pill' which is a tribute to Pac Man. It's not hip hop at all, but it's fantastic:
http://www.youtube.com/watch?v=htl_vwkZWHw