Epicurious.com
http://eat.epicurious.com/
This is the first place I go to for recipes. Every recipe I've used, albeit about a dozen, have turned out great. You can register with them and keep the recipes you find in a handy-dandy online recipe box.

Just Crockpot Recipes
http://www.justcrockpotrecipes.com/
The name says it all. If you're a crockpot fan, here's a robust site to keep you slow cooker cooking for quite awhile.

Favorite Cookbooks

Culinaria: The United States edited by Randi Danfourth The Culinaria series of books are ginormous coffee table books, not good for propping up on the counter and cooking from, but packed with food knowledge!

Culinaria: European Specialties edited by Joachim Romer

Betty Crocker's Cooky Book edited by the Betty Crocker editors I was mesmerized by this book growing up, fascinated with the sample cookie/cooky photos along the bottom of the pages. Still think between those simple photos and the spiral binding that this is one of the best book design ever. And thanks why it endures.

The All New, All Purpose Joy of Cooking by Marion Rombauer Becker, Irma S. Rombauer My main reference cookbook. Very informative and straight forward.

And of course, the Friends of Loosetooth.com Cookbook!