This past Thursday I drove from MA to VA (Williamsburg) and back last night. Each fillup (four total for the trip) had a tank average of 40.5 mpg. The car only has 4000mi on it, was loaded with suitcases and a passenger, has sticky tires ( Falken RT-615 + 15" Konig Heliums, 33psi cold all around), sat in traffic for at least 2 hours (of the 12 it spent driving) each way, and had the AC going the whole time. I was also going between 65-75 the whole time. I'm pretty damn happy with those numbers.
Sadly my scangauge arrived the day after I left, so I'll have more fun data on the next trip.
I figured you all would like to know.