Whats the best way to create interactive application prototypes?

Question

The question should be interpreted from a general point of view and not targeted solely at web apps or desktop apps.

I have been looking around to find a simple and

Answer 1

Real GUI builders are:

• Much slower
• Only programmers can use them (try to explain to analyst how to populate a table in VB)
• They don't let you annotate your mockups on the fly
• Don't have skins (e.g. black&white) to create screens which can't be mistaken for "almost done" application

While specialized mockup tools are usually:

• Communication oriented
• Can print or export your mockups (together with your notes) to PDF/HTML/Word etc
• Better ones have some variant of "master screens" so you can derive hundreds of mockups from only a handful of main application screens (you quickly get to quite a lot of mockups when you try to discuss real scenarios with your client)
• Fast enough so you can prototype realtime in a meeting

Almost a decade ago I got frustrated by all of the above and created my own tool: MockupScreens. It became pretty popular quickly :-)

And here is the most complete list of such specialized tools I know of. Many of those are free: http://c2.com/cgi/wiki?GuiPrototypingTools