Deep Purple or Led Zeppelin? Well, I hosted the Zeppelin discography discussion thread, and tattoo'd the four symbols on my shoulder when I was 18, most here know my answer to those two options.
John Lennon or Paul McCartney? I chose life over death
Frank Zappa or Jimi Hendrix? I'll go with the brother, not the weird uncle with the porn-star 'stache
Ian Anderson or Peter Gabriel? Petey, even though I should kiss ass and answer Anderson.
Greg Lake or Jon Anderson? Anderson - remembering all of the lyrics to The Revealing Science of God on the ProgNation cruise at his age while baked out of his mind on god knows what with only one rehearsal was impressive as shit
Eddie Van Halen or Randy Rhoads? Edward for his playing... not his personality
Steve Perry or Freddie Mercury? It's not kissing ass to answer Freddie... anyone who answers otherwise is ill-informed
Boston or Chicago? - Assuming you mean the bands, and not the cities or any sports franchises? If the former, Boston; if the latter, anything but Boston
David Coverdale or Glenn Hughes? Anytime I think of Coverdale, I think of 80s era Tawny, so him
Def Leppard or Bon Jovi? In support of your bro, I go with Def
Adrian Smith or Dave Murray? Why can't we have both?
James Hetfield or Dave Mustaine? Why do we have to chose either?
The Clash or The Ramones? Punk? Really?
Tom Waits or Tom Petty? As a Canadian, I must insist that the better 'Tom' options are "Stompin" Connors, or Cochrane - and I chose the latter (in both cases)
Bruce Dickinson or Eric Adams? Are they even in the same league? Dickinson, so long as he never puts his dick in my son.
Nuno Bettencourt or Paul Gilbert? Nuno wins by an edge for his flowing locks; Gilbert loses for the 70s era headphones he wears on stage
Pantera or Soundgarden? I chose death
Blur or Oasis? I chose a second death
Radiohead or Muse? Disco Metal I guess
Gene Kelly or Fred Astaire? Fred... cuz Ginger was usually close at hand.