Peter Provost says:
I want everyone who agrees with me to blog the following sentence: Unit Testing support should be included with all versions of Visual Studio 2005 and not just with Team System.
And I can't help but agree. Unit Tests, and Test-First Design, are not just collaborative practices. They're fantastic code-quality tools, for individuals or teams, and the more-widely they're spread, the easier they are to use. The Test Framework that's built in to your environment stands a much better chance of being used.