The first response to my request for debugger visualizers is from Daniel Moth. His little String Encoding Visualizer is great for anyone dealing with string encodings. It could easily become an absolutely essential tool for this kind of development. I should mention that Daniel's visualizer is based on a fairly recent CTP, which means that he won't have any problems moving to Beta 2.

Thanks for sending your visualizer in, Daniel! Everyone else, tell me about your visualizers!

[see my visualizers category for discussion/documentation and links to other visualizers]