Hybrids aren't ready for prime time. Their gas mileage is actually a joke. Unless it's getting 100+ mpg and maintaining speed and range, for a reasonable price, I'm not interested.
I’ll tell you what. I’ll bring my Prius, you bring your Geo Metro, and we’ll see who gets better mileage on a commute into DC in the morning in Northern Virginia.
In optimal driving conditions, a small-engined car will generally be able to do as well as a Prius. After all, the Prius is essentially a gasoline-engine-powered car.
What all the extra stuff does for the Prius is make it run optimally even when the conditions are NOT optimal. If you are doing stop-and-go, it captures the energy rather than wasting it heating the brakes. If you stop, the engine stops. If you accelerate fast, instead of revving up the gas engine and putting it into a low-efficiency band of operation, it throws electricity into the electric motor instead, hoping to replenish it when you don’t need the power by operating the gas engine in a high-efficiency band.
In the end, the Prius is a mid-sized car, and it will take the energy required to move a mid-sized car from one place to another. It’s a little better aerodynamically, but other than that it’s all special tricks to optimize the energy usage.
I can drive 10 miles in an hour in stop-and-go traffic, and at the end of the hour my mileage will still be 40+mpg. Try that in a car that doesn’t shut off the engine when it stops, or have an electric motor for short starts/stops.