I have been "self teaching" Japanese for about 2 years now. Most of it has been very casual, primarily watching fansubbed Japanese anime, and listening to Japanese music.
I have several Japanese dictionaries and other learning materials -- but what I have always wanted was a book that would translate Japanese word-for-word literally. This year I was given this book by a very thoughtful coworker for my birthday. It does just that.
The book will show a panel from a manga with the original vertical Japanese, then it will write the Japanese right to left, then under that it will translate each word literally. Then below that it will have a properly constructed English translation! All I can say is that this book is AWESOME!!! And so is Mike for giving it to me! Thanks!
If you are teaching yourself Japanese I cannot recommend this book enough. Pick up one right away!!!