I'm planning to upgrade to some nicer wheels for my Trek 2.1 as I plan to start racing crits and road races next month.

Everyone I have talked to about crit racing has said that aero is important, so I'm thinking about what I'd like to replace my current wheels with. Currently I have the Bontrager SSR wheels that came stock on the bike, and it's my first real racing bike, so I really have nothing to compare them to. I've started reading a lot on the forums and at review sites to try and educate myself, and now I have questions.

First, you should probably know my budget: I'd like to keep everything under $1000 US, and I'm always willing to get stuff of ebay as long as it's in good condition.

I was looking at the American Classic 420 Aero 3 as a possible choice, and saw that the rim depth is 34mm. It's my understanding that rim depth is one of the largest factors in determining aero performance, so compared to my current Bontrager SSRs, which I measured at about 25mm deep (I couldn't find this measurement online), I see that there is about 9mm more depth on the AC wheels. So my first question is: how much of a difference does 9mm make in an hour-long crit (or a three-hour road race or a five-hour group ride)? What are the big factors to think about when looking for aero wheels?

Also, I only plan to make one wheel upgrade that I hope will last me for at least the next couple years, so while I want a wheel that will be good for crits, I also want to not worry about using it on training rides or group rides that include short climbs (<1000 feet for any one climb). Is it too much to ask for a strong, light, and stiff aero wheel?

Feel free to post links to other forum posts (I know this type of question comes up often and I've browsed through several posts already) or links to suggested wheels, etc.

Thanks!