What useful plug-ins / debuggers for Visual Studio do you use (for Windows)?
P.S. I know Visual Studio has a good debugger)
Keep in mind I and the gang don't add anything that didn't come with VS. So the answer is none.
But external to VS we do use WinMerge from time to time.
I used to use the Regular Expression plugin until I rolled my own stand-alone tester.
Can you clarify what do you need? What technologies are you associated with? Different plugins can be used for different projects. There is a rich selection of plug-ins in Visual Studio
I have been using Visual Assist for over 15 years. A few years ago, I tried turning it off and using plain Visual Studio, but it didn't take long to realize I preferred many of the little things that VA does to make programming quicker and easier.