I've had my Toyota Echo for about 3 years now and still just absolutely love it. I've had no mechanical problems. I especially love the interior design. And the gas mileage is awesome. I also like the way the car sits a little higher than most cars... protects the muffler. Its such a perfect little car, I wouldn't hestitate to buy it again.
My favorite feature is probably the interior design and the stereo system. A real plus is the shelf underneath the steering wheel. Always a place to put something.