TestDriven.NET...
I came across a link to TestDriven.NET today. Given that I'm not as plugged into the C# space as I used to be, I hope this is news to at least some of you.
TestDriven.NET is a VS add-in that builds on top of NUnit to give you IDE integration for your unit testing features.
I haven't had a chance to try it - if you have, please post your opinion in the comments.