The Moth

Apart from Tracepoints (as hinted at the last sentence of that post), the most exciting debugging enhancement in Whidbey is the Debugger Visualizer support. If you are already familiar with VS2005 Debugger Visualizers, here you'll find what has changed with the latest Community Technology Preview (btw, the Dec is not the latest CTP from a framework version perspective, the Nov one is). If you are not familiar with the feature, I suggest you follow these links [ 1 , 2 , 3 , 4 ] and note the changes from previous versions detailed below:
1. The assembly reference must be to: Microsoft.VisualStudio.DebuggerVisualizers
2. The DebuggerVisualizer attribute ctor doesn't need the 3rd param i.e. delete the VisualizerUIType parameter as all visualizers are modal now.
3. Your class that implemented the Show method of IDebugVisualizer should now inherit from DialogDebugVisualizer and override the Show method; the signature for this now is:

void Show(IDialogVisualizerService, IVisualizerObjectProvider)

Of course, you need to imports/using System.Diagnostics and Microsoft.VisualStudio.DebuggerVisualizers; the location for visualizers (assemblies/dlls) is still the same: "My Documents\Visual Studio\Visualizers" or "[VS8]\Common7\Packages\Debugger\Visualizers"

That's all. If you didn't know about Debugger Visualisers and have downloaded the Nov CTP, follow the links at the top (and below), download their samples, make the appropriate changes and have fun!

Next time I'll implement a DebuggerVisualizer (not an Image Visualizer, which you can get here, here and here) so you have a complete sample to download.