Scapple is definitely mind-mapping software. It's great for working through ideas. Then when you have a grasp on what you are planning to do you can drag the idea nodes into Scrivener and it will turn them into note cards which you can think of as separate chapters or scenes.

As for Scrivener I just use the real basics. It's just a great tool for organizing thoughts, scenes and chapters. It's also good for setting up a research section to store scraps of info related to your project but are not going to be directly in the project.

Jedi Moose