Musical comedian Jared Dines got around to wondering what would happen if you play classic riffs in Drop G tuning, so he set out craft an answer. Some of 'em are miss a little more than hit, but my favorite was definitely "(I Can't Get No) Satisfaction" by The Rolling Stones. For no particular reason, the song just sounds inherently djenty tuned down low!
Other songs tossed in there are "Crazy Train" by Ozzy, "Smoke On The Water" by Deep Purple, and pretty much any of the first riffs you ever learned on guitar!