Of course, I went to all the links for tools in the post that I could find, and then some. I will probably finish reading it after I try them all :)
Here are my refinements on the lists that I've accessed, specific with .NET programming in mind and free tools:
- Nregex.com - nice site that tests your regular expressions online and let's you explore the results. Unfortunately it has no profiling or at least a display of how long it took to match your text
- PowerShell - Great tool once you get to know it. It comes complete with blog, SDK and Community Extensions
- PowerTab - adds Tab expansion in PowerShell
- Lutz Roeder's Reflector - the .NET decompiler and its many add-ons
- Highlight - a tool to format and colorize source code for any flavour of operating system and output file format.
There are a lot more, but I am lazy and I don't find the use for many of them, but you might. Here is Scott Hanselman's list of developer tools from which I am quite amazed he excluded ReSharper, my favourite Visual Studio addon.