The United States’ Department of Energy has concluded that hybrids save a LOT of gas:

The lab crunched all the statistics — number of hybrids on the road, new and old EPA mileage ratings, user-reported mileage figures, and the same mileage numbers for vehicles that most closely matched hybrids in terms of size, weight, and performance — and produced the following figure: To date, hybrids have saved 230 million gallons, or 5.5 million barrels, of fuel.

In Japan, Toyota has received approval to test their plugin hybrid:

While the car is still in testing phase, with eight plug-in OEM vehicles being manufactured and released for testing in Japan, hopes are high that Toyota will soon release this car to the general public.