Scrivener. Mac only. Member Richard Nagel recommends Scrivener highly for all phases of writing: outlining, compiling research, storyboarding, full-screen writing and editing of fiction, non-fiction, and scripts. Compatible with Final Draft for screenplays. Thirty-day free trial. $39.95 US. Academic discount.
PageFour. Windows only. Member Richard Nagel suggests PageFour as a possible alternative to Scrivener for writers who use Windows. Trial version limited to three notebooks with 20 pages per notebook. $34.95 US.