Here's a graph of my pace from my Nike+ iPod thing, and generated using WorkoutDump.com since nikeplus.com's analysis tools are pretty weak. Looking at the graph, it's pretty apparent I got caught up with the crowd at the start of the race, before settling into a solid pace after the first mile. You'll notice then that I started slacking on the pace. The explanation for that is in this elevation graph. The big hill was actually at the south end of the course next to the park, staring around mile 5. I decided I'd tough it out and make it up the hill, but the first drop is at the top of the hill when I was spent.
I had another drop in pace after the loop as I came upon the hill again. Once I got past there, I maintained a decent pace before I hit the small hill at the end, and I was pretty much spent, and I struggled to finish.
Oh, for those who are curious, I was 358 out of 514 with a chip time of 2:26:06. (I also happened to be the slowest person among 25 to 29 year olds). Whee!