These aren't new, but better late than never...
Ten Must-Have Tools Every Developer Should Download Now: http://msdn.microsoft.com/msdnmag/issues/04/07/MustHaveTools/
NUnit to write unit tests
NDoc to create code documentation
NAnt to build your solutions
CodeSmith to generate code
FxCop to police your code
Snippet Compiler to compile small bits of code
Two different switcher tools, the ASP.NET Version Switcher and the Visual Studio .NET Project Converter
Regulator to build regular expressions
.NET Reflector to examine assemblies
Visual Studio Add-Ins Every Developer Should Download Now: http://msdn.microsoft.com/msdnmag/issues/05/12/VisualStudioAddins/
TestDriven.NET
GhostDoc
Smart Paster
CodeKeep
PInvoke.NET
VSWindowManager PowerToy
WSContractFirst
VSMouseBindings
CopySourceAsHTML
Cache Visualizer
Wrapping It Up