Van Halen. Excellent demo of how to get the most convincing "overdriven guitar" sound out of a MIDI module. Check out how certain notes in the guitar solo, being played by a distorted guitar patch, are doubled by the guitar harmonics patch, in order to better simulate the natural feedback that a guitarist would get, at certain points, if he were playing with his amp turned up as loud as is done when playing this kind of music.
Van Halen. Another good example as above.
Egdar Winter. A classic instrumental with lots of synth parts.
Another One Bites the Dust
Queen. A driving bass line punctuated by guitar strumming.