The Best Frame Rate

I run a flash web site. www.neptunecircle.com
Nothing special, some funny cartoons and some crappy games.
Anyway. Right now, we’re using 30FPS. Only because it looks smoother and um, I dunno really. Anyway it looks nice how it is now.

Well we got to wondering about what are the benefits of using 30fps over 12(flash default) or like, 15(some random number)

So I guess what I’m asking is, is there any real advantage to using any particular frame rate? I guess thats it.