If you pass on The Gay Divorcee, you'll miss Rogers and Astaire doing The Continental, one of their great numbers. You can catch it on YouTube, however.
That's one of my favorites. Hang 'Em High is another favorite of mine on Instant Watch. hehe I could have gone on with the list so here's some westerns but I bet you've seen all these. They like be appreciated - Cat Ballou, Hombre, Red River, and My Darling Clementine.
There's some funky 70's sci-fi too under Classics...like the Planet of the Apes stuff....I know its an acquired taste (or lack of taste--as some of my snob friends would say, but hey, I'm a product of my misspent youth!).