Be sure to give the others a whirl as well (especially TAO which is pretty good competition for OmniOutliner). One other program also worth mentioning is Scrivener. It's a dual-pane outliner, but with the interesting feature that if you select multiple nodes, the display collapses them all into one and you can edit them together, which is vaguely like editing a single pane outline and quite similar to the old DOS program GrandView's document view. Scrivener has become quite popular lately among authors. It's also one of the few outliners which supports footnotes and marginalia directly. (You can of course define styles in OO for those things and then after exporting transform them into whatever desired output you wish when bringing your documents into a word processor for final markup.) Scrivener is here:
http://www.literatureandlatte.com/scrivener.html

One thing to also keep in mind is that modern Macs can run Windows programs in a "virtual machine" (i.e. at the same time they're running Mac OS, with no slowdown... in fact, you can even set it up so Windows programs appear on the OS X dock (its equivalent of the taskbar) and behave basically like OS X apps), so would be possible to get away with just one laptop at work and at home, if you really found you liked the platform.

If you're looking for a good program for cross-platform file synchronization (other than just carrying around a USB key with your documents on it and plugging it into whatever machine you're working on at the time, or keeping all your files on a networked file server accessible via VPN), take a look at Unison:
http://www.cis.upenn.edu/~bcpierce/unison/
It's a free piece of software developed by some academics. A lot of people swear by it.

-- Chris

ndodge wrote:

Thanks Chris, this was very helpful. I may try out Omni on a used Mac. Thing is is that I'd
need two -- one for at work and one for at home - I don't want to always lug a laptop back and
forth and sometimes I need my PC laptop so I don't want to have to lug two. I just
discovered a neat use for parallel views in ecco, so for the time being ecco is keeping
me entertained. But it sounds like Omni might be a great ecco replacement and more
which is still being developed. Not sure I want to deal with syncing 4 computers
though. Syncing two is painful enough, as syncing software just does not seem to work
entirely robustly (foldershare, beinsync, powerfolder, etc). But getting two
older macs used might not be as expensive as I thought, as you mentioned, Omni doesn't
seem like too demanding of an app -- If I can do writing, use Omni, do a little surfing and
email writing that's all I probably need to do on the Mac.