One needs only to look at my DVD collection to find my favorite. Sci-fi hands down. I have every Star Trek episode ever made and broadcast from the Next Generation as well as the first six Star Trek films featuring Captain Kirk. I have some of other genres, but Sci-fi takes up more than 75% of my total media collection (not including games).
-Unferth
I would have to pick Drama as my favorite movie genre, as it is my favorite TV genre too. My TV choices are all the Law & Orders, CSI Miami/LasVegas, The Shield, Rescue Me, and likewise, any movie that deals with crime/sex/drugs/rock-n-roll. I loved Memento, Requiem for a Dream, Blow, Collateral, Final Destination(s), etc. In the survey, I picked Musicals because I love performing and they always make me want to fly outside my door and sing down the street.
It's a hard choice, but I voted for Sci-fi and Fantasy. There's both action and adventure in such movies, something of a comedy, something of a thriller, of a horror and more. Basically, in sci-fi and fantasy motion pictures there can be everything, but the different reality - whether in a fantasy world of elves, dwarves and warriors, or in a universe of space travelling - cannot be replaced.
Naturally, I enjoy movies that take place in today's world: action movies (Jackie Chan comedies!), comedies, adventure (I love the Indiana Jones series), thrillers and horrors, animations, but dramas a little less. I find most of them boring.
My favorite genre is actually action drama, but that wasn't one of the choices so I chose drama because to me it's the dialogue that makes a good movie