Honestly would you say music by "the doors" is a different genre then say "Jimmy Hendrix"? Possibly but if your like 90% of normal people you'd classify it as rock or classic rock.
I dunno, I'd like to see more balkanization of rock genres -- it's not helpful to me, when hoping for indie/dance crossover stuff such as the Stone Roses or New Order, to see it tagged with the same genre as interesting-but-not-my-cup-of-tea stuff such as Rush or The Darkness, or flat-out drivel such as Bruce Springsteen.

Peter