I have a lot of faves:-

Nigellas
Jamies
Martha Stewarts Baking Handbook (this is my baking bible)
Baked (by some guys that run an awesome NYC Bakery)

But my absolute overall cooking bible would have to be Stephanie Alexanders Cooks Compendium (I have two editions and one signed!)
Second to that would be Larousse Gastonomique
And then a few others...

I have a mammoth collection so its hard to pick one