Madeleine L’Engle herself, back when she was still alive and spry, reading The Wrinkle in Time and the other books in that series. In the sample, she has one of those interesting New York voices.
The Lincoln/Douglas Debates, read by David Strathairn as Lincoln and Richard Dreyfus as Stephen Douglas. This is a brilliant idea for an audiobook, and a must-listen if you have any interest in American history. Needless to say, it’s probably not the most comfy listen; it’s not fun to hear Douglas talking about slaves as if they weren’t people, and Lincoln saying only what he thought Illinois voters would be able to take. (IIRC, Illinois had no legal black residents at all, slave or free.)
Caedmon’s Edgar Allan Poe Audio Collection. Well, I know I had you at “Caedmon” if you’re an old school audiobook listener. If not, you should learn that Caedmon did extremely high quality literary audio recordings, often of deservedly famous writers reading their own works. This collection gathers together various old recordings of Poe material done by Vincent Price (!) and Basil Rathbone (!!). So yeah, that definitely is a keeper.