My first question is what type of food are you looking to prepare they are 1000s that could be reccommended. I guess if you want a good all around book the Joy of Cooking would be a great start its in local bookstores in paperback as well as hardback editions.
There are numerous discussions like this in the Cookbook forum. Like Cakerookie said, it's kind of hard to make recommendations without knowing a bit more about you, your interests and skill level. I also agree that "Joy of Cooking" is a great all-around cookbook for the home cook. Please checkout the Cookbook forum, as it is full of great ideas.