Ideally recipes that actually taste good and maybe some that are quick and easy with few ingredients :)
Deborah Madison's encyclopedic "Vegetarian Cooking for Everyone" is a really great cookbook. Many of the recipes are vegan, and even more could be made so with simple changes (substitute another fat for butter, omit a dairy garnish). In addition to very good recipes (from simple to more involved) she includes a lot of discussion of basic ideas for how to choose and cook each vegetable, type of grain, etc.
I concur with zombiecupcake and will also recommend ALL of Isa's cookbooks. I am not vegan but cook her recipes all the time. It's just good food.