I mentioned that Mark Millar's and Bryan Hitch's Ultimates face two external threats, the Chitauri shape-changing aliens and international super-terrorists, but there is a third. When the super-terrorist invasion is being defeated, Loki summons Surtur, Ymir, trolls, dragons and giants. We also see the World Serpent, Garm the Hel Hound and several other giant hounds.
Thus, like Hitler in The Last Days of the Justice Society, Loki initiates an early Ragnarok and Thor retaliates with reinforcements from across Bifrost, thus proving his divinity to everyone who had thought that he was a mental case.
Fire and frost giants withdraw, presumably to return at the eventual Ragnarok.
Addendum: Maybe Roy Thomas' The Last Days of the Justice Society and Young All-Stars 1-6 belong on the list of definitive superhero restatements?