There are so many! The most poignant LGBT movie for me personally was Another Country, which was sort of my coming out film. Had a terrible crush on Rupert Everett back then and that film helped me feel proud to be gay, as did Maurice years later. There's a whole collection of off-beat LGBT films from Mysterious Skin to Hedwig to Boys Don't Cry to The Joy of Life that would make my top 10 list. Being a film festival junkie, sometimes my favorites are the small films I see at a festival like the documentary on Bayard Rustin, Brother Outsider, which I saw at Sundance and led to proud tears for this gay civil rights leader.
(Cross-posted on QMovieBlog.com)