I'm going to give what I think are the top five sort of essential cookbooks for vegans. If you disagree, please let me know, always looking for another good cookbook.
(1) Moskowitz and Romero's Veganomicon. This is the one, folks. It single-handily rendered half a dozen otherwise wonderful vegan cookbooks obsolete. Basically, all the other books on this list are optional, this one is a requirement. It is the Joy of Cooking or Mastering the Art of French Cooking, but for vegans. It is a teaching tool, you learn how to make things, and from there you can make your own recipes.
Sarah says, "What I am saying is that Moskowitz &Romero are the faces of vegan cookbooks for our current times. They make recipes that are interesting and unique that don't rely heavily on processed goods."
(2) Tucker and Enloe's The Artful Vegan. This is the high class, gourmet, time consuming but it is worth it, vegan cookbook.
Sarah says, "You have to make the ginger cookies. You *have* too."
(3) Dieterly's Sinfully Vegan. This is the best multipurpose dessert cookbook. The cheesecake is particularly good. However, Moskowitz's Vegan Cupcakes Take Over the World is a lot like Veganomicon. It teaches you a lot about what it means to cook vegan cupcakes. So, while Sinfully Vegan has a better spread of desserts, Vegan Cupcakes has a better teaching and training.
Sarah says: "Sinfully Vegan, while yummy, is one of the better health conscious vegan dessert books. It doesn't merely tell you to add more sugar to everything."
(4) Stepaniak's The Ultimate Uncheese Cookbook. One of the things I missed most as a vegan was cheese. Basically, everything is fairly easily replaceable by non-animal sources. The Uncheese Cookbook really is wonderful for replacing animal cheese, and a lot not just based on nutritional yeast.
Sarah says: "When you are getting a hankering for the meltyness of cheese, and you don't live in a major metropolitan area, this book is the cure."
(5) Okay, so I don't have a good answer for five. What you really need to do now is get books that reflect the subset of food you particularly like. Romero's Viva Vegan is great for Latin food (and like the Veganomicon, teaches what it means to cook Latin food). Noyes' American Vegan Kitchen is great for that vegan diner food (though, a lot of the stuff her recipes call for are hard to find in your grocery store). Klein's The Mediterranean Vegan Kitchen and Vegan Italino are book solid, with lots and lots of recipes (but doesn't do a lot to teach you how to go about thinking and cooking mediterranean and italian food).
Sarah says: "After a while, what you need is to have several books to get ideas from, and play around with, but not make direct recipes from them all. Get a sense of how you like to make food, and mix and match and change to your own delight."