When you know you will watch a movie with a girl, and you get to decide what you would play, then the first thing to consider is whether you go to the cinema, or watch it at home. If the former, then you need to pick something romantic, and steamy, probably with a pinch of erotica.
However, if you are at home, then the choice is easier, and there is no need to watch an entire movie that does not keep your interest. At home, you can put on almost anything, since you can pause and rewind it if you are turned on. Porn is obviously a great choice, but a girl is not likely to appreciate it.
Horror is probably your best bet, since it urges her to get close to you and seek comfort, so it will be a lot easier to kiss and fondle her until she finally gives in.
Also, there is one more choice, but it is risky. You need to decide which movie she will find boring. Keep in mind that your opinion is not always the same as hers. And unfortunately, most women find action movies – the ones with no special effects – boring so you might want to sacrifice one that you are not going to see or what you have already seen.
Those ones that both of you find exciting and that keep you awake are the worst that you can pick, especially if they are long, as well, since you will be tired before you could get naked.