…The Rocky Horror Picture Show!
Second place goes to Footloose.
My taste is in my mouth, so there have to be better ones out there. Maybe a Fred & Ginger movie. Though they rarely had more than 3 or 4 songs, they were usually by one of the greats, like Irving Berlin, and I’m not sure how original to the film they were.
ETA: My wife would vote for the soundtrack from Patton, but she’s demonstrably crazy.
ETAA: Happy Kyne did the music for the real “Flight of the Phoenix?”