XMLmind's XML Editor
DocBook is a great tool for any documentation writer, but it can be a real pain to get adjusted to. I had decided to use it for the fwbackups 1.43.2 user guide the end result was great (less a few spelling mistakes), but coding it by hand took a long time and isn't something I would want to do again
I have been using XMLmind's XML Editor to rewrite the documentation for fwbackups 1.43.3 in DocBook 5 and it's been great. It has a WYSIWYG interface and although the program has a small learning curve, once I got used to the hotkeys my productivity went way up. Version 4.6.0 (released about two weeks ago) also includes a new Link tool can be enabled in the Preferences (under General > Features) that is excellent for creating cross-section links in your documents. After giving a section an xml:id name in the Attributes section, highlight a piece of text and select Edit > Add or Change Link... from the menu. All of the document's xml:ids for will be listed and selecting one will create the link automatically.
The license for the personal edition license allows XMLmind's XML editor to be used to write documents for any open source software (as defined by the OSI) - if you need a quick way to write great looking documentation, consider paying XMLmind's website a visit.