As far as I'm concerned, OmniOutliner Pro is one of the most useful Apps on Mac OS X. If you haven't tried this App, you're really missing out!

Very handy - I'm using it for tons of things such as:

• keeping to do lists
• tracking serial numbers
• writing documentation for people
• note taking

I must have ten to twenty OmniOutliner Pro files in use already - and you can even link them together by dragging aliases from one to the other. So if you have related lists, you can click an attachment in one list to jump to the other. The control over styles with the floating style sheet is simply amazing - very innovative! Also, the dynamic HTML export is amazing - you can even fold the rows up and down!

Anyhow - it's hard to extoll all of the virtues in this small space - head over to the Omnigroup website for some nice screenshots and ideas of what you can do with this app.