For me, it would be Avatar.
Now I don't want to get a lot of hate mail, but even though I liked the special effects and good story, I kind of thought it was a bit contrived and pretentious. I mean, there is no doubt the movie was preachy and holier-than-thou, and it was also kind of forced in that the story was grossly unrealistic. It wasn't about plot-holes, actually the plot was good. But it was more the logical fallacy that spear wielding tribesmen could defeat a highly trained modernised force, even if that force was comprised of mercenaries and driven by corporate interests.
If history has taught us anything, it is that idustrialised armies ALWAYS win a war. As a historian, I just simply cannot get over this problem with the film. Plus, there is the obvious problem of when a bigger company, or a stronger mercenary force, or even a friggin nation-state and its army moves in to clean up.