First off, great topic! Secondly, I've got to admit that the debut albums by The Doors and Led Zeppelin were the first two that came to mind.
However, I think "All Things Must Pass" by George Harrison qualifies. "Wonderwall Music" was a film soundtrack and a vanity project; plus, it was released while he was still in the Beatles. "All Things Must Pass" was a proper debut from him as a solo artist. I'd also give a vote to "Grace" by Jeff Buckley.
"Honorable mentions" for the debuts by Crack The Sky and The Pretenders.
However, I think "All Things Must Pass" by George Harrison qualifies. "Wonderwall Music" was a film soundtrack and a vanity project; plus, it was released while he was still in the Beatles. "All Things Must Pass" was a proper debut from him as a solo artist. I'd also give a vote to "Grace" by Jeff Buckley.
"Honorable mentions" for the debuts by Crack The Sky and The Pretenders.