It's a Wonderful Life

This film is a "1946 American Christmas fantasy ... The film is one of the most beloved in American cinema, and has become traditional viewing during the Christmas season. The film stars James Stewart as George Bailey, a man who has given up his dreams in order to help others, and whose imminent suicide on Christmas Eve brings about the intervention of his guardian angel, Clarence Odbody (Henry Travers). Clarence shows George all the lives he has touched, and how different life in his community of Bedford Falls would be if he had never been born. Despite performing poorly at the box office due to stiff competition at the time of its release, the film has become a classic and is a staple of Christmas television around the world." This was taken from Wikipedia where more information is available.