Hell so many to choose from but.....
Chuck Berry - All catagories (Ok forget "My dingaling")

BB King
John Lee Hooker
(Ok Blues/RnB out of the way)
Black Sabbath (I still don't think any other band can imitate their sound).
Deep Purple (Gillan, Lord, Paice (Sp)? Blackmore) Lineup
ELP (Showed all the other 70's "Synth" bands how it should be done)
Alice Cooper (Creativity/Originality - Just go see him live)
Rolling Stones (You can't stay up there for 40 years without being at least a bit good -Whoops slipped back into RnB)

Grateful Dead, Are they still alive?
Mike Oldfield (For originality)
Jimi Hendrix
Lynard Skynard (A sound all of there own)
Dory Previn (Who)???

(One of a kind - trust me)
Artists like Clapton, Gary Moore, Mark Knophler (Sp)? all worthy of a mention but only as masters of their art not as originators
TTFN
snafu