Walt Simonson run... Loki gets defeated quite easily by Thor:
The story is: Thor wants Loki to take back a certain spell. So Thor just rushes in, grabs Loki, beats him up, destroys some illusions cast by Loki with ease, grabs him by the throat and throws Mjolnir very far away (so that when Mjolnir comes back into Thor's hand, it will automatically meet Loki's head). In the next panels, you see Loki surrendering and doing as Thor wishes.
You see, defeating Loki can be very easy if he isn't prepared. That's why I have no problem with the Hulk/Loki scene in the movie. At that point, Loki had already taken repulsor damage from Iron Man, got beaten up by Thor, he had Hawkeye's arrow exploded in his face, and the Hulk surprisingly tackled him. He was very weakend and very confused, and still believed he was in control... his arrogance made him believe that the Hulk is only a primitive animal. So Hulk could beat him down easily. Makes perfect sense to me.