Just one entry for today.

I was looking around for a free XPath expression tester online.  Surprisingly, it took me at least 20 minutes to find a free one.  Altova XMLSpy Home Edition, while free, does not include an XPath evaluator (it's an add-on in the professional edition).

However, I did find Dimitre Novatchev's excellent (though ugly as hell) XPath Visualizer.

Great tool (although the UI is ugly)!  And you just can't argue with free