n no particular order, ten of the most useful free tools for .NET developers:

• Fiddler HTTP Debugger
  HTTP debugging proxy
• Lutz Roeder's .NET Reflector
  .NET assembly browser, explorer, analyser and decompiler
• FxCop
  .NET best-practice code analyser
• C# Snippet Compiler
  Lightweight C# code snippet compiler
• Sysinternals DebugView
  Monitors debug output on a local or remote computer
• WinMerge
  Visual text file differencing and merging tool
• GhostDoc
  Visual Studio add-in that automatically generates XML documentation
• CopySourceAsHtml
  Visual Studio add-in that copies syntax-highlighted code to the clipboard as HTML
• NUnit
  Unit-testing framework for .NET
• SQL Prompt
  IntelliSense style auto-completion for SQL Server