1# Jack Kirby and will always be King and #1
#2 Frazetta...best of the best artistic wise and great with other artists such as Al Williamson etc, would be #1 but for limited output..I know quality not quantity.
#3 Steve Ditko ...his 50's 60's SF work is the best and incredible, ASM 1-38...what more can I say..
#4 Wally Wood, artistic wise, probably during his EC peak the second best comic artist of all time...SuperduperMan, Atomic Bomb, My World etc
#5 Dave Stevens...again like Frazetta limited output...but simply amazing stuff when he is "On"...as time goes on, we as comic book historians will really see how important style wise his contribution to our comic book world, a incredible loss to leave us at such a early age, but a true true fan from the heart.