Ok, now you got me started......
"Band" circumvents the composer label, limiting things a bit.
"Best' also is quite an ambiguous term.
Groundbreaking:
The Beatles, Meshuggah, Metallica, RATM, QOTSA, Fleetwood Mac, Stevie Wonder, Dead Kennedys, Buddy Holly and The Crickets, Nirvana (although they built on the punk ethos), Little Richard (come on, a black guy in the 60's who wore make up....? How brave is that...?!?), Andres Segovia and
John Williams (the guitarist), and Pink Floyd (the guts to pursue their own ambitions when it wasn't cool to do so),but the kings of all were Bach and Handel. Without them, music as we know it would not exist. Foo Fighters? Poor cousins of greater rock ideas.
RHCP? Again, poor cousins of greater funk/punk minds.
Guilty pleasures: AC/DC, The Algorithm, Prodigy, Dire Straits,
Strapping Young Lad, Aphex Twin, Front 242, etc.
You get the idea.