Just to follow up some of the interest in ouliners last night. Here are the links.
Buzz is a wxPy application. I would definetly spend some time checking this out. The author clearly has strong vision for what he wants in an outliner. He has an extensive feature list that includes things like XSL-FO, Word HTML in/out, OPML (for you Dave Winer aware folks), vCal and PDF support.
Treeline is a pyqt based outliner that is fast and usable right out of the box. It's gui is organized around panes in which as you navigate nodes of your tree as they come up in the preview/edit pane. The basic tree manipulation keybindings are immediately useful which goes along way with me. He has definetly spent some time with his documentation.
http://www.xecu.net/dougbell/treeline/index.html
Of the two I will probably be spending most of my time with Treeline.
By the way, if anyone doesn't want to leave their command-line, Woody is a great outliner as well. It is available in Debian (and freshmeat has an old project page) but I couldn't tell you the current status...
I would very much like to hear what conclusions other people with outline interests come to.- Adam
Check out Leo