I know that I may seem fickle with so many nominations here, but I've finally settled on the greatest recorded album of all time. I base my decision on overall recording/mastering, musicianship, and ability of the artist to reach that special place that transcends the ordinary and becomes...extraordinary.
The album for me must be Muddy Water: Folk Singer 24/96. I don't know all the history of this recording. I believe that it was recorded in a few hours with one mic. The recording is sublime. The music is presented with great nuance and refinement for such an antiquated record (original recording 1964). You will hear some of the best guitar licks and riffs of all time. Previously no one did this better than Clapton, but after carefully comparing Clapton's Unplugged with Muddy's Folk Singer I would have to give the nod to Muddy. His voice exudes the blues. Listen to the quiver of vibrato as he belts out these tunes. Some are ballads and some "foot stompers." The atmosphere of the room where these men made this treasure is captured perfectly.
If you care anything about the blues, the roots of rock and roll, or just great music then you must treat yourself to this one.