There is no one best setting. It's a matter of what kind of device or media player you're creating the movie for. Read this page about frame rate.
Since you're new to After Effects, I very strongly recommend that you begin here:
It depends on where the footage is required. Usually, people upload the videos to Youtube or a similar video community. They recommend around 30 fps:
When you think about it, when you post up the video with really high fps, you can't assume people who watch will have that high of an fps as well.
ummmm... i got it.. and what is the best setting for fps like columbia pictures, 20th century fox etc for they making their videos? are they use 30 fps for make their movies or they have another settings?