I'm running my stock tires at 42 PSI and my MPG for this tank is currently 49.9 MPG in the past 212 miles. My most recent trip today was about 65 miles and I got 57.5 MPG... I'm using all the tricks I've read here, such as accellerating a bit fast then getting off the gas... Oh, and driving behind semi trucks to help reduce wind resistance. Hot_Georgia_2004 has an EXCELLENT article on this site for driving tips.

Just my $0.02.