I use good old fashioned HTML. It has several advantages: - You can easily change it, even when in front of a customer/user - You can get actual interaction.

I use good old fashioned HTML. It has several advantages: - You can easily change it, even when in front of a customer/user - You can get actual interaction. Flow and what happens when you click different links, how pages are linked, etc. is an important part of an interface. - You can use it as a starting point for coding - You can easily put it on the net so that customers/users can click through it in their own time, not just when you're there.