Isn't it funny how charging for a genuinely useful tool has to be explained?
TD.NET is a mainstay of our .NET development team and TDD without it seems barbaric. :-) In fact, when we have had problems with TD.NET (weird problem while using VPN a while back that made tests take forever - something weird with the remoting bits) and it was just miserable. A quick way to discover your dependencies is to remove them and see how it hurts!
Jonathan: agreed :)
TD.NET not free - not even a small tiny version - has really hurt me. My company is run by politics, which means that we can only use certain tools, and to add new ones to the list of approved ones takes right about 12 months (not exagerating). TD.NET is not on the list, and it will never be on it. VSTS is on the list, but the cost is prohibitive.
NUnit & NCoverage have been the main tools for p/a's first line of defense against bugs, albeit "illegally".
I can still use the tools "stand alone", but just makes it harder without the add-in.
Wasn't it an O/S project at one point?