Godzilla. Not only is he the "King of the Monsters" but he also holds the record for "Longest Living Monster", "Most Victories against Other Monsters", "Most damage to Human Cities", and "Most Unkillable".
In Godzilla vs. Megaguires, the Japanese government built a Black Hole Gun and blasted him with it, and he still survived.
Also, no other monster you can mention has survived anywhere NEAR the amount of firepower that the Big G has. Lasers, Masers, Mech versions of himself, Navy vessels, you name it he fought and destroyed it.
Big G has also never defended humans. He never stepped around a building or protected people. He just defends his territory from other monsters.
Also, the Hollywood Godzilla's name is Zilla.