I remember the first time I saw Lost Horizon. It was on tv, and I loved it. Based on a James Hilton book, the 1937 film is directed by Frank Capra and stars Ronald Coleman, Jane Wyatt, Sam Jaffe and Edward Everett Horton. The film has its own Facebook page.
The movie can be watched online, thanks to GoogleVideo:
Moria calls it "most certainly an overrated classic." In a review released at the time, the New York Times says it's "a grand adventure film, magnificently staged, beautifully photographed, and capitally played." Variety praises it.
12/30/2009: Shooting Down Pictures has a thorough article, including videos and lengthy excerpts from other sites.