So, by the numbers: I came in 7,109 of 26,242 overall finishers (about the top 25%); 391 of 2062 in my age group (about the top 20%); ran the second half very slightly faster than the first half (19 seconds faster, to be precise -- this is a good thing); and had a 9:09 pace overall (faster than my training pace).
May I say that I was really quite pleased with myself?
More generally, it was a great day to run. Everything went perfectly for me as far as getting there, parking near the start (my little secret!), watching the elite runners sprint off, and laughing at the costumed runners. The speedo-ed "Michael Phelps" certainly encouraged me to get past him, and some people I knew won first in the group contest with a great Ms. Pac-Man theme. The weather was perfect. The waves were nicely timed, so there weren't too many slow people to dodge. There were bands and spectators all along the course, and then there is the course itself, which is just one of those perfectly lovely places that makes me glad to live in Richmond.
Pictures later if I buy them!