Open source: Far from a reason not to use .NET
I love the little holy wars that go on in various forums about why .NET sucks or whatever. Those who state this are generally folks that have never used the platform. One of their key “arguments” is the lack of open source community around it.
I'll admit I've never bought into the open source ideology as something that will save the world, but I've been really impressed with all of the open source tools in the .NET world. I personally have used NUnit, Nant, NDoc and FIT, among others. Heck, I give away POP Forums too.
I've grown pretty fond of NUnit in particular, since outside of my “day job” I've been really breaking stuff down to little pieces and actually practicing test-driven development. I feel like such a corporate tool, but it's such a great way to get stuff done and make it quality.