I like the Gerswin piano Preludes. The "Brigadoon" discussion reminds me that Gene Kelly choreographed some dances to these Preludes for his 1958 TV "Omnibus" episode, "Dancing: A Man's Game." They were adapted for orchestra by Saul Chaplin, I believe, and it was neat to see Kelly dancing to Gershwin again.
I must throw in my vote for BK's giving "Brigadoon" another chance. I think I heard it's being given an improved DVD release soon. (And I in turn promise to take a second look at another stagebound musical adaptation that never wowed me, but which I think you said you liked, "Li'l Abner.")
A highlight, and one of the few accidental improvements from the otherwise unfortunate decision to transform "a singer's show" into "a dancer's film," is Kelly's softshoe solo "Almost Like Being in Love." He makes it into a similar sort of jubilant goof in the manner of "Singin' in the Rain," but without the puddles, and it's hard to imagine it working better on film as a duet (which it was originally on Broadway) even if the casting was right.
I think I read that Donen had wanted to do "Brigadoon." It might have turned out pretty well had he directed Howard Keel and Jane Powell in it, even if it had been shot entirely indoors. "Seven Brides for Seven Brothers" was also shot mostly indoors, wasn't it? Yet it was able to capture the kind of energy (Michael Kidd's choreography was a big help) often lacking in "Brigadoon," and managed to beat the kilt off it at the box-office.