20. Metallica (Season 18 Episode 1- "The Mook, The Chef, The Wife And Her Homer")
If Metallica decided to roll through Springfield anytime in it's first 10 years, when Metallica was still somewhat relevant and not busy fighting the winds of change with their lawsuit over Napster they would have made it far higher on the list. As is, for this band to wait 18 years to become Springfield-worthy is a surprise; especially when you consider some of the other bands that hopped on the Simpsons bandwagon years earlier. The episode itself involves Metallica meeting their biggest fan who turns out not to be Otto but Hans Moleman.