I told you about going mostly vegan, and now I want to share some of my favorite cookbooks for vegetarian recipes. These are not vegan cookbooks (or strictly vegetarian, for that matter), but they have plenty of recipes that will inspire your cooking:
Plenty: Vibrant Recipes from London's Ottolenghi is a killer cookbook that will inspire anyone who loves to cook. My only complaint is that many of these recipes require a lot of prep work, so it's not the best choice for weekday meals. Try Ottolenghi's recipe for leek fritters for an introduction to his food.
A relatively new-to-my-collection book, Vegetable Literacy, is an amazing book and a true labor of love. Deborah Madison is the mother hen of vegetarian cooking, and this new book will really make you think about vegetables. I recently made her cauliflower with saffron, and it was a lovely recipe. Madison's Greens Cookbook is another long-time favorite of mine.
How to Cook Everything Vegetarian is one of those cooking reference books that any cook will find incredibly useful. The recipes aren't eye-opening, but if you have a vegetable that you're not sure how to cook, Bittman has ideas and recipes to help you out.