Can't find a vid for it, but the 2 minute intro to Dieselboy's Project Human mix-cd is probably my favorite. It's got the dude that does movie preview voice-overs talking about how you've entered the future, robots are taking over, rogue-scientists are trying to save us from annihilation, etc. Sick intro, and totally gets you in the mood for the dark/techy DnB that is to follow.
If it has to be an actual song then I would have to pick
Zao - The Buzzing on their Parade of Chaos album. Back in '02, this shocked me when I first heard it, and I loved how this disc just tore your face off from the very get go. Still can get pretty hyper when this is on.