On a trip to New York while I was still in high school, my parents brought back a vinyl copy of One Way Out by Sonny Boy Williamson. My life was very different from that point on.
I was already fascinated by the raw, scratchy sound of acoustic Delta blues, and in this record I discovered the blueprint for translating that cathartic energy into a Chicago studio. Williamson is often called history's best harp player, and he earns the reputation on this limited-edition collection of his classic work for Chess Records. The metal positively melts on tracks like "Let Your Conscience Be Your Guide," "Cool Disposition" and "One Way Out."
In Williamson was the savvy studio polish of B.B. King and the primal immediacy of Son House. These personalities argued. They pushed and pulled. They resulted in the best blues record ever recorded.
(If you can't track down a copy of One Way Out, the more comprehensive The Essential Sonny Boy Williamson is a great alternative.)