I won't provide a happiness top-ten but I will say that Danny Boyle's Shallow Grave and the first Trainspotting film always cheer me up. Weird I know but they really do. I find the actual endings of both films to be extremely uplifting. I watched Singin' In The Rain fairly recently and that film is also worthy of note. The majority of James Bond and Star Wars franchise films are also usually 'happy' films for me.
