Mine has to be Sci-fi. I love the opportunity it brings to the table. It can range from a wide variety of plots and places, even some of the duds I find to be great! My favorite movie all time though has to be Kung-Fu Hustle! What are some of your favorite Sci-fi movies?
Unsurprisingly to me Sci-fi and Fantasy are at the top in the board. Same for me, to be honest. Especially when all the fantastical/magical/alien/tech-filled world building works as a stage to explore basic human nature, different ideologies/ideas etc. Even though it's always been seen as 'lower' than "Literary fiction", I find speculative fiction is possibly the most important for humans to explore what can be. I mean, see Star Trek or any Le Guinn novel, really.