I just paid 3 bucks a gallon for gas. My problem is that I always wait too long to fill up my tank and am never able to look around for the cheap station. I was having some fun with this site to try and find cheap gas near Craigorian Chant World Headquarters. Of course, most of the time, this is only going to be useful once I get a car with wi-fi and a heads-up internet display. Or how about a car where I can just ask "KITT can you find me some cheap gas?"
I would also recommend this Billmon post on politics and gas prices and oil and foreign policy.