I have the Everyday Cookbook of course and I love it. Even if I alter the recipes, it takes the guesswork out of most dishes.
I also have the Vegetarian Cookbook and the Cyndi O'Meara one and I use those equally for meals.
I have the Varoma Cookbook (Full Steam Ahead) from my recent demo and it's pretty, and full of amazing ideas, but I haven't actually used it yet!
And I have a folder with recipes I print from friends, blogs, here...
I kinda like cookbooks and would like to get the budget one next.