Mark Bittman's
How to Cook Everything is my go to cookbook, and I have tons of cookbooks. He has reliable simple recipes, with a lot of bang for the buck because after each recipe, there is a list of simple variations you can make to drastically change the dish.
And, there are different 'levels' of recipes too. For example, there are 4 waffle recipes, all the way from an elaborate mix you prepare the night before to a quick one you whip up just before breakfast.
http://www.howtocookeverything.tv/
I also like Alton Brown's
I'm Just Here for the Food and
I'm Just Here for More Food, but they're really more like funny textbooks on the science of cooking, with few actual recipes. They do make you understand how cooking works though, so you can make wise choices.
And as far as Celebrity Chef cookbooks, I like Jamie Oliver the best. His latest cookbook
Jamie's Kitchen has great recipes for fresh foods (he keeps chickens!!), and you can watch him cook the recipes in the book on his Food Network show on Fridays. He has a new book coming out very soon that I'm sure I'll pick up. I just adore him. You can see free recipes from him here:
http://www.jamieoliver.com/recipes
I have so many cookbooks, it's insane! And I cook from them rarely, but I read them cover to cover and kind of integrate it all into how I cook. I lean towards authors who tend toward fresh, simple foods without many processed ingredients.
Edited to add links!