Seeing as the Hulk gets his power from his rage and Atrocitus uses the power of rage as a power source. The more angry the Hulk gets the more powerful Atrocitus would get. 

Personally I have to go with Hyperstorm, he is the ultimate Omega level mutant. Like come on even before absorbing Galactus's powers and going on a rampage throughout the comic universes, the DC, Marvel, Anime, and Darkhorse universes I think, he was mega powerful and a  super genius. He is even more intelligent than Reed Richards his grandfather. He has the power of every god, demon, mutant, enhanced being, animal, alien race, robot and cyborg. Ifs thats not the best bunch of powers nothing is. He is even more powerful than the Living Tribunal.