Even if you are an experienced cook, it's very useful to have at least one general cookbook on your shelf. 

A good general cookbook will include basic recipes that you can adapt to meet your needs.  It will give you appropriate cooking times for a variety of dishes.  It may also provide useful instruction on basic techniques and equipment.

Two books you may want to consider are the Martha Stewart Cooking School or Cook with Jamie (Oliver).  Both are about teaching the basics and providing a variety of recipes that you can use in your daily life.

Specialty cookbooks are great, but they can't be the entirety of your collection.  You need a basic book you can turn to when you need inspiration for a family dinner or to craft a dinner party menu. 

I have lots of cookbooks.  I can read them like novels.  But honestly, some of them just aren't practical.  They use unusual ingredients that you'll never use up or they require dozens of steps that will rarely fit into a busy life.  That doesn't mean you shouldn't have those books, just that you need to make sure your collection is founded on a solid base.

Any other favorites you'd like to recommend?