I saw a link to Keynote somewhere on the forums. It looked interesting, so I decided to download it.
I had tried RoughDraft one year, but the tabs didn't really compensate for all the other stuff in Microsoft Word. Keynote (although not in further development anymore) is far more hierarchical and possibly more in line with how I think. It's not linear and it's not non-linear (certainly not as splattered around as the snowflake method or a spidery free-for-all like FreeMind), but it is organized, so I think I'll give this a go.
Maybe I'll give an update on how this software is faring in mid-November.