Nine Inch Nails - Last.
Broken is well-loved and remembered for Wish, Suck and Gave Up, not to mention the infamous Happiness in Slavery video. Last is one of the best rock(y) songs NIN have ever made and virtually everyone ignores it. Hell, it was released in 1992 and Last got played live for the first time ever in 2007
Probably have to say the same about Getting Smaller from With Teeth too...