Scrivener is like Hermione Granger’s bottomless handbag. You can import research documents, web pages/links, and photos right into your project, so even when you take your laptop on the road, you have everything you need. You can also import any writing you already started in another program.
Plus, you can keep outlines, notes on ideas for changes and future scenes, and character and setting information all within the project. No more scouring your hard drive or that pile of sticky notes on your desk for a crucial piece of information.
Scrivener is AMAZING, and so is Gwen Hernandez -- she's a Scrivener guru.