Found a really interesting new diff and merge tool for the Mac: Kaleidoscope. Native app, integrates with Versions, Cornerstone, and the command line. Looks promising.
Just came across a Test Data Builder implementation for .NET, Autofixture. The Test Data Builder pattern has become quite popular recently since it was mentioned in Growing Object-Oriented Software, Guided by Tests. I've used the pattern before, but I've always built the builder implementations by hand. This implementation looks really promising.