Genesis until 1975
Derek and the Dominos
Humble Pie
Creedence Clearwater Revival
Point of trivia that reinforces the Allman Brothers at the top of the list for me:
I truly believe that the studio version of "Layla" by Derek & The Dominos was the greatest rock song ever produced. Duane Allman played slide guitar on the studio tracks for that album. Eric Clapton heard him playing at FAME Studios in Muscle Shoals, Alabama back in 1968, and knew immediately that he wanted to have him for the "Layla" tracks.