Killzone 2's E3 trailer. I don't even care that the graphics weren't anywhere near that. I cared about the action. That trailer looked like it was finally going to give me what I wanted: war. I wanted a game where I was part of an army, storming areas with dozens of allies, while other soldiers were dropping around him. I wanted to feel like I was in the heat of battle, and not this one man killing machine, or part of a small squad of soldiers who get everything done. I mean, look at this:
Sadly, the game turned into the same thing as before. One or two good levels like that, and then surprise, surprise, you're by yourself or part of a small team of unkillable friends.