I like many of the films mentioned so far. And if you want to venture a little further, I recommend:

from Japan: “Okoge” (おこげ Fag Hag), dir. Takehiro Nakajima, 1992—one of my favorites.

from Hong Kong: “Happy Together” (春光乍泄), dir. Wong Kar-wai, starring Leslie Cheung and Tony Leung Chiu Wai, 1997—really well done.

from China: “Lan Yu” (蓝宇) dir. Stanley Kwan (who is HK, but the film was based on a Beijing cyberstory and mostly done by mainlanders), 2001—not perfect, but a nice try.

from China: “Farewell My Concubine” (霸王别姬), dir. Chen Kaige, 1993—a major film but alas very stupid on the gay theme (but on the plus side a good performance by Leslie Cheung again).