Harold and Maude is a 1971 dark comedy/romance directed by Hal Ashby and starring Ruth Gordon, Bud Cort and Ellen Geer (who has a Star Trek connection). The music is by Cat Stevens. The film is on several "top" lists, including 3 from the AFI. There's a Facebook page.
It's online at Googlevideo:
The New York Times doesn't like it. Roger Ebert doesn't like it either, saying, "Harold is death, Maude life, and they manage to make the two seem so similar that life's hardly worth the extra bother." Variety makes it 3 for 3, opening with this: "Harold and Maude has all the fun and gaiety of a burning orphanage."
6/16/2010: 366 Weird Movies calls it "my all-time favorite for about as long as I can remember".