Pierre Henry Track that was reworked for the Futurama theme (track comes in at around 1:50 but the prelude and stuff is awesome too)
See I think early electronic composers like Stockhausen are a little off topic as they are fairly far removed from the beat driven stuff that was mentioned by lazerbeat in the original post but anything that gives me an excuse to go into an art-music post fest I will take
Stockhausen's most famous works are probably Gesang de Junglinge and Kontakte (kontakte being one of the best in my opinion) his later stuff gets ridiculous like Helicopter quartets and the like..
Pierre Schaeffer
Morton Subotnick (winner of coolest name in early electronic music)
Edgard Varese