I'm always a guy who sometimes finds it more relaxing to use an old fashion database known as the book.There's far too many I own than I should post about inorder to keep this brief so I'l just mention my two most important:
I've had this book before I even got my first Pokemon game. It wasn't much use since Emerald war my first, but it taught me some of the basic ideas and concepts of Pocket Monsters altogether.
This book has all sorts of useful charts that helped me in Emerald before I effectively learned to use the internet to find these things. Since then I havn't needed to get many guide books, but this was a great book and it's been worn down by years of use which to me means that it has done its job.
(Also I'm hoping this is the most ideal subforum to discuss this)