Well Hell, Sandy! If yer goin' for "anthologies" you don't have to make those "hard choices", like I just did. Here's a couple of others though.

From Smithsonian Folkways: Autoharp Styles. American Banjo-Scruggs Style.
Electra put out a fabulous 4 or 5 record set many years ago...very well rounded. Would love to know if it's on CD.
By the way. Gargoyle might not like the commercial aspect, but I bet he approves of the music choices so far.
Rick