Gonna start this, because his latest CD is a dead set classic, Born and Raised. Fine Country Blues with tasteful production, superb songwriting and guitar playing.
Jackal has already mentioned the guys personality, which unfortunately is his nemesis in a lot of ways.
I never rated the guy until an apprentice at work (who is a guitar nutter, like me) begged me to watch Where The Light Is. Well, I gave in, and as anyone who has seen the first 20 mins or so will testify, I was blown away by the fingerpicking and singing.
Mayer still manages to soil the event by letting his personality speak during Bold As Love, such a shame, but still amazing.
Continuum is an amazing classic mature album, so is the new one. I have his early CDs, but I never listen to them.
I'm going out on a limb to say Knop fans would like Born And Raised, it's very subtle.