Indeed the finest music ever deviced my mankind. SID music was orginally made for C64 and nowadays (some) people emulate it by using programs like SIDPlay. The greatness of the Commodore 64 sound system can clearly be heard. This music *slightly* resembles MIDI music.
The incredible (ok not to any sane person, but I don't claim to be sane) part is that this great music fits into few kilobytes and still lasts for minutes.
The High Voltage Sid Collection is probably the largest collection of Sids in the world. It includes tens of thousands of Sids with information from the Sid Gods themselves.
Best known tracks include the Commandos highscore track by Rob Hubbard and the Last Ninja Tracks by Ben Daglish and Anthony Lees.
Many of the tracks are a great testomony to the fact that great music is not made by high tech. The technology doesen't matter if you have the talent.