Well now we know that Thor's evil half-brother Loki is the main villain along with some army that has yet to be revealed in the upcoming Avengers film. However, I'm just wondering if you think Loki and his army destroying New York is a good choice or if you would have done some different story with a different villain including:
1) Red Skull who leads a stronger HYDRA army that march on Washington DC using the Cosmic Cube to take over the United States
2) The Leader who would try to turn the people of the world into an army of Gamma mutants.
3) Crimson Dynamo teaming up with AIM to take over New York
4) Maybe Loki doing something similar to the Acts of Vengeance storyline where he gathered the foes of the various Marvel heroes to defeat them.
5) Surtur, the Frost Giants, Hel, and the Dark Elves leading an army to invade Midgard.
6) Kang the Conqueror trying to take over the world
7) Ultron trying to start a Terminator-like world where machines kill humans