I think this is a leak in my tournament play: I catch myself worrying about whether I have an average stack sometimes even when the blinds are not that big a deal. In fact, I think one's stack should be measure relative the BLINDS and not to the remaining field.
Here's my argument: Let's say you have a stack of T,3000 and blinds are 100/200 in an 18-player tourney, just to make things completely clear. Well, if there are only 5 players left, you're actually in way BETTER shape than if there are 9 left. On the other hand, with 5 players left, average stack is something like T5,500, but with 9 players left, you have an average stack. So, measure in terms of stacks, you would seem to be worse off.
Conclusion: In worrying about survival, sure, look at the stacks you may or may not want to attack, but it's the BLINDS that you have to consider in terms of desperation levels--not the opposing stack-sizes.
Anyone care to disagree?