Recently, Brian Kernighan gave a lecture at Princeton talking about "The Changing Face of Programming".
(Warning: PDF Link) The Changing Face of Programming - Brian Kernighan

We tend to really like paper prototypes in our line of work.  We often find that by just doing three or four prototypes that we have significantly increased our knowledge of what the client needs up front.
Techniques and tools are discussed at introspectiveH.

User Interface Engineering (UIE) has an interesting podcast discussing some of the problems when using wireframes for complex designs. They cover issues like preserving context, explaining why interface elements are there (or not), and setting priorities for what can be cut.  Keith Robinson call his solution the Page Description Diagrams which describe what the wireframe [...]