James Avery creates a list of ten add ins a visual studio developer must download.
This contains following add ins.
TestDriven.NET
GhostDoc
Smart Paster
CodeKeep
PInvoke.NET
VSWindowManager PowerToy
WSContractFirst
VSMouseBindings
CopySourceAsHTML
Cache Visualizer
Wrapping It Up
here is the article link for that...
http://msdn.microsoft.com/msdnmag/issues/05/12/VisualStudioAddins/