I have to say that my absolute BEST treadmil song is SANDSTORM!!! If you get the 8 minute track of it you can run the WHOLE thing and just cut it back half a K in the slower parts. I also like Call on ME- Eric prydz for running!
Other songs that keep me pretty amped are:
Ramstien - du hast. (das is gut!)
technotronic - move this
and toxic (britney)
Kings Leon, Alk3 and foo fighters are perfect for kicking around weights though!!!!