If the gutter is wide enough, you can have them rebound with spiral binding. This is incredible useful for holding or putting a book flat. I did this to all my textbooks in college.

I don't understand why Cracking The Coding Interview never published a two volume spiral bound book. It's the perfect candidate: it's huge, you're referencing two different sections regularly, and you stay on one page for quite a while. I never ended up doing it to my copy though.

This is probably just a personal quirk, but I despise spiral bindings. I hate the feel of them. They never hold together. They catch on everything and come apart. Pages get torn far more easily. They make the books - if you can even call spiral-bound stacks if paper that - more difficult to organize. They suck.