Ever since I discovered snippets in Visual Studio 2005, I've been using them like crazy.
Microsoft has a good list of pre-canned snippets (http://msdn.microsoft.com/vstudio/downloads/codesnippets/) in 13 different categories.
But the best category of snippets I've found thoroughly covers NUnit code templates. It's located here: http://www.codeproject.com/dotnet/UnitTestCodeSnips.asp.
Combining these NUnit code snippets, with TestDriven.Net (http://www.testdriven.net/) and it really makes it easy to practice test driven development