I’ve often wondered why there are no good tools for easily developing information architectures and producing wireframes.

Visio tends to be the standard, although I regularly use PowerPoint due to its ubiquity. Thanks to the PowerPoint Prototyping Toolkit you can produce quite good results.

The problem with Visio (other than its cost) is that it tends to get pretty fiddly/messy. Sometimes it seems that I’m spending more time fighting with the software in order to get everything laid out properly than actually designing.