In addition to the above I would also add Document's "Country Gospel (1946-1953)", which contains the entire output (eight songs) of Sister O.M. Terrell. The rest of the CD is dedictaed to Two Gospel Keys, but Sister Terrell is worth the price of the whole thing.
As for another Sister, that being Rosetta, you can either go the Document route or buy the Proper box set "Sister Rosetta Tharpe - The Original Soul Sister". The set contains eighty-one songs, and the accompanying booklet has greqt notes and dozens of fine photos.
The "as good as it gets" gospel entry, "Black Gospel", has 56 tunes on 2 CDs, and is a terrific sampler of early gospel stylings.
Finally, someone mentioned "American Primitive Vol.1", and that's an excellent choice. The recently issued Vol. 2 has less of a gospel focus, but "There's A City Built of Mansions" by the Nu Grape Twins is stunning in the extreme. And if anybody out there has figured out all of the words to this (or even some of the words), please post them here!
