Another Mac program that some people use for fiction writing is Journler http://journler.com/ It has many devoted users and a responsive developer. I think it was originally designed with keeping a journal and writing in mind, but has developed into one of the top-rated information management programs for the Mac. (See for example: http://danieljomphe.wordpress.com/2008/01/31/8-web-information-collectors-reviewed/ )

I have relied more on Scrivener, but purchased Journler because I can already see its usefulness for gathering information and making notes. It has smart folders and smart folder families, and is really set up well for tagging.

Randall