I don't have enough "real" cookbooks besides the Better Homes and Garden one, which sucks because it's full of bland, uninspiring recipes that are a little too 1950s casseroley for me.
But you do need classic, "bible" type cookbooks. I only have thin, not-as-useful ones that I got as gifts, like a tapas cookbook, an Asian vegetables cookbook, a "best-ever chicken" cookbook and some random international cookbook. I also have two dessert bibles (Great Desserts From Great Chefs; Dessert Circus), and those are very good. But I need more bible-like ones for other foods and other types of baking. Cooking is a religion, and you need textual inspiration and affirmation.
Books for which I intend to scour Liberal College City's used bookstores or get on my next book budget or birthday, which I also suggest to you in order of importance (e.g get the high-ranked ones first, the Chez Panisse ones are not as necessary to building your store of skills and ideas):
How to Cook Everything by Mark Bittman (this is like the New Testament)
Barefoot Contessa at Home by Ina Garten (I like books for home cooks; too fancy and you'll never make them)
Jacques Pepin's Table (out of print, but a good book!)
The Tartine Bakery Cookbook (the best bakery in America)
Mastering the Art of French Cooking by Julia Child (low ranked only because the above are more versatile and cross-cuisine)
The Chez Panisse Cafe Cookbook (the slow foods movement: a good idea, hard to keep up, hard to sustain in less agricultural parts of the country)
Chez Panisse Desserts (the Tartine book is better)