I think Zeppelin was absolutely great at rockin' the Blues...HOWEVER...considering Lennon and McCartney would not only produce some great Blues riffs themselves (i.e.: "I Want You/She's So Heavy", among many other tunes), but L&M (and least we not forget George Harrison) also managed to make great music in the Rock and Roll, Pop, Rockabilly, English Music Hall, Hard Rock, Country, Ballads, Psychodelia, Instrumentals, Soul, Folk, Indian and Symphonic genres.
And so, because of their mastering of all these different varieties of music, I have to say I think The Beatles were "the best".
(...and don't forget, IT WAS The Beatles that started the whole "British Invasion" of the '60s, and creating the impression among the American Youth of the time that British musical acts were "cool")
