"X-Unity" -- an xUnit-like TestingFramework, intended to support ExtremeProgramming's UnitTests.
Price: Reasonable -- $100 +
See: http://x-unity.miik.com.ua/
The user interface strikes me as excessively chatty, and not set up properly to handle the *LARGE* number of tests one would expect in an XP project. (This is my first impression, based on looking at their web site. I'm not currently doing DotNet work.) -- JeffGrigg
[Opinions from people who have actually tried this product are certainly welcome. -- JeffGrigg]
CategoryDotNet CategoryTesting: TestingFramework for RegressionTesting of (MicrosoftDotNet) components and applications.