An XSLT template editor

XTrans
Free
Offline
http://sourceforge.net/projects/xtrans/

XTrans is an XSLT template editor, which also allows you to test XPath expressions.
The program does not need installation: you have to unzip the zip file into a folder and run the XTrans.exe program. Before installing XTrans, you need to have MS Visual C ++ 2005 installed.