Man, there's a whole lot of white folks being name-checked here ... which is fine, but in the interest of throwing a bit of color into the mix (so to speak):
Marvin Gaye, What's Going On - It took me awhile to appreciate the brilliance of Marvin Gaye and it's hard to argue that this was a seminal work, both for him and the label. There's plenty of great Motown production to point to, but in a whole lot of ways this album sounds unlike anything that came before it.
Sly and the Family Stone, There's a Riot Goin' On - I'm convinced this is what heroin sounds like. When I was first really digging into R&B and funk, I overlooked this album because it wasn't the raucous Sly sound that immediately grabbed my attention. This is a great post-bar-time record and was, for years, the album I'd put on after a long night on the town as I waited for the bed to stop spinning. In retrospect, that may not have been the wisest choice, but damn it's fluid and soothing. In my opinion there's not another quite like it, before or since.
Stevie Wonder, Innervisions - Another brilliant all-hours-of-the-night record and a great headphone excursion. This album is deep, sonically speaking and otherwise.
Worth noting that these albums share the distinction of being produced by the artists themselves.