I'm based in the UK, so all mpgs below are in UK gallons....

I used to drive a Hyundai Coupe (Tiburon in the US). However, the ride was a little poor on UK roads and we wanted something a little more economical - we were getting about 25mpg on the motorway (cruising at 70 mph). So, we changed to the new Ford Fiesta and stepped down to a 1.4 litre engine. The mpg at 70 is about 50mpg. Slightly better...

I was driving downhill over the weekend at 40 in 5th gear and reset the mpg meter. For the next quarter of a mile, the it showed 99.9mpg. OK, so the sample size was a little small, but still it was nice to see!

The only problem is that I'm still used to being able to accelerate in the Coupe and the Fiesta feels a lot slower past 30mph.