8.Tony's Bound To Die If He's Not Careful...
While any superhero runs the risk of dying in the heat of battle, Tony Stark is the weakest and most vulnerable of the "super powered" Avengers. His power doesn't come from Gamma radiation infused DNA, nor from some sort of Government Science Project or just being a Norse God. Tony's powers come from actual power, expended from the usage of actual hard to find (and extremely cost prohibitive) elements. We take this fact for granted and kinda forget about it when caught up in the middle of the action, but Tony's suit is powered by the arc reactor built into his chest. A reactor that was, in the beginning, built in order to prevent shrapnel from penetrating his heart, thus effectively killing him. Now, imagine all of the power he has to burn through to do all of the neat stuff he does in his Iron Man suit. Factor in how much Starkanium (or whatever his proprietary element is named, but admit it he'd name it after himself) he burns through to keep that reactor going on a good, superpower free day; then expand that to how much he must burn through when he's going through something like The Battle Of New York. That's a lot of energy he's burning through, and ultimately that doesn't sound good for him in the long run. Tony can't play the hero forever, and with the sheer volume of villains being thrown at him and the intensity of their attacks, this promises to be the most strenuous challenge of his life. He should quit while he's ahead, or else he'll lose his head.