I would check out your favourite preggo and baby books as most of them develop a series. If you liked a certain layout or style there, you might be able to continue to enjoy it! What to Expect has a toddler book, as does The Girlfriend's Guide (an American series - very funny, but some good advice, too, I thought).
You also start to get into some of the parenting/education philosophies, so you could check out things like Montessori, Waldorf, etc.
Oh, one that we bought because we heard the author talking on the radio and were really intrigued was "Raising Boys" by Steve Biddulph. It's a simple book about boys and their typical development and how to meet their needs. Both husband and I found it to be quite thoughtful and straightforward. It's not just about toddlers, though - it's boyhood through teens to manhood.