Optimal Frame Rate?

Hello all –
i am getting ready to post my first flash webpage and i am trying to decide on a frame rate. the flash (all preloaders, all effects, all everything) is 100% actionscript so (as far as i can tell) increasing the Frame Rate doesn´t increase file size. But just in general, what are the considerations in deciding on a frame rate? I want it to run as smooth and fast as possible, is there any harm in setting the frame rate to 120? Any advice would be great,
best.b