And then there's the Jesus theory. Some theorists pick up on a religious theme running through Felina, with Walter sacrificing himself to save the people he loves the most: his wife, his kids, Jesse. 

breaking Bad alternate endingWalter White In The Final Episode of 'Breaking Bad'

The first reference could be the Sangre de Cristo Mountains (The Blood of Christ Mountains) - which Walter notes that the Schwartzes can see from their living room. The second is Walter's injuries which could be interpreted as the Five Holy Wounds. Finally, in the last shot, Walter's arms are outstretched as if in the shape of a cross. 

Speaking with Entertainment Weekly, Gilligan said, "So it could be argued that he pays for his sins at the end or it could just as easily be argued that he gets away with it."

Thanks to The Atlantic Wire and Esther Zuckerman for picking out some of the best Breaking Bad theories.