The Animals : We've Gotta Get Out Of This Place
[purchase]
Great bass lines are sometimes quite simple. Other examples : Ray Charles' "What'd I Say", Michael Jackson's "Billie Jean" or Pink Floyd's "Money".
You'll learn a lot about the song on this great Wikipedia article. The bassist is Chas Chandler (the last guy on the right on the picture), who was Jimi Hendrix's manager and who helped launch his career.
I'm posting this from my office, at lunch break. I really gotta get out of this job.