Perfect Debute Albums

Depending on what you consider their first album, my vote is is for

The The - Soul Mining.

Runners -up:

Laurie Anderson - Big Science
Emerson Lake and Palmer - self titled

David

Gregg Allman, Laid Back

Christopher Cross...swept the Grammys that year if I remember correctly.

pepe

Ben Howard's Every Kingdom is a masterpiece.
Alt J's first album an Awesome Wave is very near perfect as well, and the freshest sound I have heard in years!

Just a few more:

Joe Jackson - Look Sharp
Elvis Costello - My Aim is True
Bruce Springsteen - Greetings From Asbury Park
Marshall Crenshaw - Self Titled

and some more post band/solo debuts of note:

Paul Simon - Self Titled (He recorded a different debut album before joining Simon & Garfunkel, but this was the first commercial release)

All Things Must Pass - George Harrison

Graham Nash - Songs For Beginners

Meet John Doe