Are there any disadvantages to having a flash menu navigation in the header? So that when visitors click on a menu tab, it does something fancy like flash. I don't see many websites do this...why not?
Not everyone has flash installed on their computer -- or will download a proffered plug-in -- due to security or accessibility concerns. James
Use Flash only when you want to impress people at the cost of your site being buried by search engines.
Ahh you are flash haters Sure, you are right that flash sites being buried by the search engines. But it depends what is the porpouse of your website, isn't it? Back to the main question.. you are right there is no sence in making only a flash menu navigation, flash is better used for animations.
Some sites are meant to impress people and source of their traffic is not search engines. Such sites have a lot of flash and some of them are really impressive. If you need good positions in search engines then you can make just banners in flash but not a navigation.