As someone who just bought a 2010 EX w/Nav (I had to because I wanted the bluetooth) and understands that she overpaid because of it, I'd say go with an aftermarket -- the fact that the nav system doesn't have traffic makes it virtually useless. At least here in the SF Bay Area where traffic is a constant concern. I'm still using my iphone to gauge traffic before choosing a route, which is annoying.
When I was shopping last month there were a lot of 2010 EX's with and without Nav that were going for about 18,500+. I got mine, with only 19k miles on it for $16,250 and added on $2,000 for 120k Honda Care, which was worth it for me. I searched and searched for a Certified pre-owned in that price range and wasn't finding anything so ended up just going to a dealer that doesn't certify cars but offers the inspection and extended warranty for around the same price. Wheel and deal and you might walk away with something for less than what the insurance co. appraised at!
Good luck - glad it held up so well in a bad crash! Makes me even more glad I chose this car