paradise
I read the Foundation series long ago; the Robot series a bit later. I have to admit Solaria always seemed a bit like paradise to me. I like to imagine myself on gigantic estates waited on by dutiful robots, and no one around to get in my way.
The lack of crowding seems especially attractive. Also, the lack of neighbors, especially obnoxious drum-playing neighbors.
Also, Absolute Power!
Here's an article that uses Solaria as a springboard to a discussion of friendship. It's not earth-shatteringly insightful, but it touches on a lot of very interesting points, including "the remorseless eroticization of human relations that was bequeathed to us by Sigmund Freud." That evil man.