Two cool things:
My wife and I have gotten our 2001 Subaru Outback to over 30mpg on most of our recent gas tanks, even hitting 32mpg on occasion, and still learning. All I have done some work on the front grill, put on wheel covers, and pumped up the tires. I believe most of it is due to our driving techniques which we have mostly gleaned from this site. Sweet! Thanks to this great community
Second, I got a chance to prove that driving knowledge is a huge part as I flew up to Alaska and drove back with a couple friends. Obviously, we had plenty of chances to change drivers, usually after a full tank of gas. I brought my scangauge to help us out. There were 3 of us, one friend got 21-24mpg, another got 25-27mpg, and I got 28-30mpg. I drove a little slower, but just trying to conserve up and over hills (instead of flooring it...) and general awareness definitely payed off. If only we had to pay for the amount of gas we individually used instead of splitting it three ways!