A couple of tire shop guys told me to run closer to the maximum pressure stated on the tire than the recommended pressure stated on the filler cap. They set my tires at 40psi. The Bridgestone tires that came on my car as so bad that increasing the pressure didn't hurt the ride. The car feels a lot lighter.
My daily round trip commute is 30 miles and takes 50 minutes. I get about 17mpg. If I can throw in some time cruising at 75-80mph, I get about 19mpg.
When better fuel economy becomes more important than sheer mass, I'll trade my car for an LS400. Despite a bigger and more powerful engine, they routinely get 20mpg or better with barely a thought.