I own a 2003 Highlander non-hybrid (which I absolutely love), and I have a couple suggestions. First, inflate your tires to the max cold psi on the sidewall. Sure the ride is a little stiffer, but it's supposed to be an SUV, right? On second thought, I'm going to do this on every car I own (car manufacturers lower the psi to give you a softer ride; Remember the Ford Explorer/Firestone debacle where they were basically arguing about the safety issues caused by underinflated tires?).

Second, you have to give a hybrid a little time to break in, as several posters have sugested. Maybe there's a little time needed to break in the driver, too.

After we bought a HCH for my wife, I once thought the Honda with its instrumentation might teach me to drive for better gas mileage on the Highlander. But the Highlander mileage has gone from a consistent 21.5 to 18.5. That's because the Highlander miles have gone from 1900/month to 500/month, because we're pushing lots of miles to the HCH because of the gas prices, and obviously a lot of the "best" miles are going there too. So you could say that for 1200 miles per month we're getting 46 miles per gallon vs the Highlander's 21, an extremely good improvement (they should use this statistic in calculating the benefit of a hybrid).

My guess is that they still have to scale up the hybrid powerplants a bit, before the larger vehicles are getting the same percentage improvements in gas mileage as the lighter vehicles. But every part of this experience tells me that we will all be driving cars like this soon.