If you really want some intense, but awesome reading, anything by Julian Sprung is well worth the money spent! And he has books on corals, inverts, and even a paperback page-turner on algae (well.... I found it to be an interesting read).
Scott Michaels has a decent pocket guide to fish that gives a quick reference.... but I find that it undershoots minimum tank sizes at times.... most of the time. However, I have often found that it's a good thing for newbies to have, since you can stick it in a purse or an oversized pocket. This way, you can get a quick heads up on concerns about keeping a particular species of fish, especially if you're at an LFS that you aren't absolutely certain about their knowledge level (or honesty).