If you have to compare the two, which is semi-pointless, then Jimi is the better of the two because he was a true innovator that influenced an entire generation of guitar players and singers. In a time of strumming folk players, Hendrix came onto the scene like a psychadelic gypsy and blew people's minds. Ozzy to this day says that Jimi was the greatest thing he has ever seen onstage.
And although technically a great player, Clapton is just another blues player who carried on the tradition of the great artists from the 50's Chicago blues scene. Cream did influence alot of bands, but they did nothing really groundbreaking. The Yardbirds and John Mayall were pretty innovative groups though. Also.... Clapton is an arrogant prick.
also every1 who is good at a ceratin thing is good at it in a different way just like in soccer ppl say pele was the best others argue maradonna or bobby charlton - IMO all were gr8 in their respective time but i wont like to name 1 greater than others .......
I'll stick with Pete Townshend from The Who as my favorite. Eddie Van Halen is solid too. But, IMO innovating smashing the guitar has to count for something!
Depending on the genre of music listened to I have to say that I respect any genre of music that doesn't lean on or is down right dependant on digital enhancement or production. Don't get me wrong, I was/am a fan of techno/trance, just appreciate the value of music that is purely manmade. That is a talent.