I was just in that Avril thread and thought it would be fun to use MIT's new Pantheon tool (ranking people throughout history based on popularity/fame) to look at all our faves! I've included overall #s too on the singers/musicians I thought were most relevant on ATRL.
Top 10 Musicians
1. Bob Marley (#176)
2. Jimi Hendrix
3. Bob Dylan
4. Michael Jackson (#262 overall)
5. John Lennon (#317 overall)
6. Avril Lavigne (#387 overall)
7. Louis Armstrong
8. Lady Gaga (#402 overall)
9. Eric Clapton
10. Paul McCartney (#474)
Top 10 Singers
1. Elvis Presley
2. Britney Spears (#280 overall)
3. Eminem (#334 overall)
4. Shakira (#370 overall)
5. Édith Piaf
6. Johnny Cash
7. Kurt Cobain (#385 overall)
8. Frank Sinatra
9. Rihanna (#440 overall)
10. Luciano Pavarotti
Other ATRL Faves
Bjork - #23 musicians, #890 overall
Gwen Stefani - #63 singers, #2160 overall
Adele - #110 singers, #3428 overall
Madonna - #16 musicians, #587 overall
Beyoncé - #20 singers, #805 overall
Angelina Jolie - #6 actors, #272 overall
Jennifer Lopez - #18 singers, #758 overall
Justin Bieber - #17 singers, #671 overall
Justin Timberlake - #37 singers, #1440 overall
Lana Del Rey - #155 singers, #4786 overall
Katy Perry - #25 singers, #978 overall
Ke$ha - #188 singers, #5313 overall
Demi Lovato - #24 singers, #927 overall
Did I miss your fave? Check for them here:
http://pantheon.media.mit.edu/rankin...-4000/2010/H15
You can search your fave in the overall list, and then click their name to find out where they rank within their profession. Keep in mind MIT's warning at the top -- a difference of a few places is not statistically significant, although bigger differences definitely are.
Lemme update the OP 
