OK, I've had my X-Terra since April, and just turned 13K on the odometer. Ive gotten about 20MPG since the 2K mark, and most of my driving is freeway. I get about 350m per tank, and put just under 18gal in at a time. I upshift at 3000rpm, and down shift at 2000rpm, leaving me at 2500rpm in 6th gear doing just under 80mph. The AC is blasting when required because I agree that the wind disturbance caused by open windows will exceed the draw in HP of a AC compressor. I am happy with the mileage I get, and 2 of my co-workers drive H-2's and have had to park them due to fuel cost.