To be honest Flash sites can be a bit disturbing for me too.

The best thing about flash is that if the graphics is really good, it will convince the visitor to stay for a little while. But consider this: some people might be using old systems and they might not be able to view the flash graphics. Also, sometimes flash sites take time to load and if the visitor gets impatient they might just close the window (I find myself having to resort to that sometimes). Make a list of the pros and cons and see which outweighs the other.
