There are many: Purple Rain (Prince); Electric Ladyland (Jimi Hendrix); Led Zepp. II (Jimmy Page); etc. But my all time favorite album that defines the artist is ANTHOLOGY by Duane Allman. If you listen to it, it clearly demonstrates what he was all about. From the BB King Medley, to Loan me a Dime, to Layla, to The Weight, to Statesboro Blues, to Little Martha (My favorite), to Dreams. They're not all Duane's, but they're all about Duane.