Some swear by Julia, some by Ina, others by Jamie Oliver. But personally, I'm a Irma and Marion girl. My friend (and the best boat cook ever) Jesika introduced me to the Joy of Cooking, and Michael gave it to me for Christmas. And I love it.
It's where I get my banana bread recipe, my focaccia/ pizza dough recipe, advice on cooking new vegetables and grains... and while it may not be as fancy as some of the newer specialty cookbooks available, it's where you can go to learn how to cook a dish perfectly and then, of course, embellish from there.
But for example, off hand, do you know what the primary ingredient in red flannel hash is? Or when the best time to eat Menudo is (not the boy band!)? Or that pink peppercorns are not true peppercorns, but berries from the Baise rose bush? Well, ok, maybe you just don't care. (But FYI, beets are what makes the hash red, and Menudo is a spicy Mexican soup that has tripe and calves' feet and is supposed to cure a hangover, thus best consumed on New Year's Day. Yikes!) But I definitely think this book is worth having on hand for the next time that someone tries to assert firmly that they KNOW what chowder is and how it's different from bisque. Think about it.