Altova Authentic® 2007 Desktop Edition
http://www.altova.com/products/authentic/xml_document_editor.html
http://www.altova.com/simpledownload1.html
XML Marker
XMLFox
XML Pro
Microsoft XML Notepad
2007
EuroMath2 WYSIWYG XML
Editor
http://euromath2.sourceforge.net/userdocs/overview.html
XMetaL Author (30 day free trial)
http://www.xmetal.com/en_us/products/xmetal_author/index.x
Review
of XML Editors
http://ahds.ac.uk/creating/information-papers/xml-editors/#section2