3. Iron Butterfly, "In-A-Gadda-Da-Vida" (1968)
http://www.youtube.com/watch?v=urGHap53sgA
"In a gadda da vida, honey, Don't you know that I'm lovin' you, In a gadda da vida, baby, Don't you know that I'll always be true."
Speaking of incredibly long songs, this one clocks in at slightly over 17 minutes (seventeen minutes of RAWK, man), but at least you didn't have to sit through it in church. Originally entitled "In the Garden of Eden," there are several common accounts of how this song came to be known as "Inna Gadda da Vida." As you may have guessed, each of these accounts involves one or all of the members of Iron Butterfly being "drunk, high, or both." Sounds about right.