We start with Mumford and Sons:
Mumford and Sons: Fleet Foxes
Oasis: Blues Traveler (don’t say Blur. Don’t ever say Blur.)
Coldplay: Yellow
Beatles: Beach Boys
Kinks: Stones
Who: Led Zeppelin
Foo Fighters: System of a Down
Tom Petty: Hearbreakers
Bruce Springsteen: E-Street
John Mellencamp: Pink Houses
Pink: Areosmith
Dream On: Dream Until Your Dream Comes True
Joe Perry riffing: Conan O’Brien
Morrissey: Kevin Max
James: Oasis
REM: Third Day
The Police: U2
R2D2: Not The Droids You’re Looking For
Chris Cocca 
Interesting that you thought “Beatles: Beach Boys”. My buddies recently had a mind-numbingly long debate about which of the two was the best pop music group of all time while I was trying to play poker.
It’s the Beach Boys…and that’s exactly why my mind went there. Band for band is a harder analysis that Brian Wilson vs. John and Paul. Wilson >.