My wife has been averaging 28mpg in her Hyundai Elantra GT. I borrowed it for the weekend and managed to hit 35mpg. *Patting myself on back* I didn't do anything out-of-the-ordinary, really, I just paid attention to jack rabbit starting and braking.

One of the advantages to her car is that it has a trip computer with your trip's average MPG displayed. Nowhere near as slick as a real-time monitor, but still pretty cool. It's amazing how I could adjust my driving habits/speed/etc based upon the readout going up and down.

I think that ALL new cars should come with a real-time MPG display.