Hemingway's house is great. I've read several of his books and wouldn't really consider myself a fan, but the house is really steeped in history and the tour is a hoot. Plus, I'm a cat lover so that does it for me! All those adorable little guys and gals running around and lounging in the Key West sun, soooooo funny!
The house is neat to see just for the architecture and design. They also have a nice little gift shop that sells everything from magnets to painting to, of course, books.