I used to have a similar problem, I live in area that has roughly 85,000 people and had lived here for 15 years without meeting another atheist (doesn't usually come up in conversation). Then around 2006, after Richard's book came out, I went to CafePress and ordered a couple of T-shirts and a sweatshirt that had ATHEIST across the front in big block letters. It's a pretty conservative area, so I thought I'd get crap from a lot of people. Just the opposite happened. Of course, I'd get the occasional dirty look or nasty remark, but 90% of the people who commented were positive (I like your T-shirt). Many, and I mean many, stopped me, introduced themselves and we had pleasant conversations. I made some pretty nice friends, all fellow atheists. Try it, it works.

I don't recommend this for everyone though. I did have a couple of clowns that I thought were going to fight me and were abusive. One guy in Home Depot was screaming "heathen bastard" at me, until the store employees kicked him out. I thought I was going to have to pound him for a while and then sue his ass for a hate related assault.