Prototyping a web application (follow-up)

My question about how to prototype a web application received interesting feedback.

I was talking in the beginning about HTML and ASP.NET, but the discussions brought some other expected and less expected answers. In the end, we can conclude that prototyping is a complete process in itself.
The cited tools include Photoshop, Powerpoint, Visio, Denim, etc. and a very praised one: POP ...Plain Old Paper!
But read the feedback by yourself. Thanks to those who participated to the survey ;-)

The feedback includes among other comments a full length post from Udi Dahan. Subscription recommended, btw!