GhostDoc is a free add-in for Visual Studio that automatically generates XMLdocumentation comments for C#. Either by using existing documentation inheritedfrom base classes or implemented interfaces, or by deducing comments fromname and type of e.g. methods, properties or parameters.

Getting old, but the "Internet Explorer Developer Toolbar" provides several features for exploring and understanding Web pages.

Essential for getting up to speed learning LINQ, as well as LINQ to SQL.

A CLR class browser with XML documentation viewer, type search, disassembler and C#/VB view.

Nice little tool :-)

Sandcastle - Documentation Compilers for Managed Class Library

A good free file/folder Diff/Merge tool (found out from thefreecountry.com, of course)...

TestDriven.NET makes it easy to run unit tests with a single click, anywhere in your Visual Studio solutions. It supports all versions of Microsoft Visual Studio and it integrates with the best .NET development tools.

Absolutely brilliant! Free Programmer Resources

TortoiseSVN is TortoiseCVS for Subversion. Enables Subversion commands directly in Windows explorer.

You've just got to check this out. As small as SQL Server Compact, just about as powerful as SQL Server Express. Pretty amazing.

The one and only, fantastic, awesome, fast, free source control server.

VisualSVN Server is a package that contains everything you need to install, configure and manage Subversion server for your team on Windows platform.