It's hard to find a decent self-service car wash, but we hit the jackpot with Surfer Express.
I just bought a new car and am washing it weekly. While I prefer a full service car wash, a self-service outfit really fills the bill between such washes as well as after it's rained in terms of pain in the pocketbook. While Surfer isn't the cheapest around, it's the best for your money if you're going the self-service route.
It's a comprehensive wash, with lots of options. My favorite aspect of this place is the blowers. They really get the car dry, which isn't the case at most places. I have minimal touching up after the wash to do, and the vacuums are the strongest I've ever seen. There's also a compressed air blower to blow the water out of nooks and crannies.
For the price, you can't beat Surfer Express. While no self-service car wash will match a good "manned" place, this comes as close as you'll get. My only complaint is that they need more locations!