We recently joined the eco chic and bought a Toyota Prius (a loaded "package 6" in black). I thought we were buying a new car, but the Prius is really just a big gadget on wheels. We've had loads of fun messing with the Bluetooth phone stuff, backing camera, and the display that shows how the power is flowing around between the engine, brakes, and batteries.
The GPS mapping system has a really nice, sharp display -- much nicer than anything I've seen in a German or American car. The routing seems pretty solid and the performance is good.
We've also messed around with the voice recognition system, but they give long instructions after you push the button for each command ("After the beep, please say the command you might maybe want me to try and process even though you talk like a drunken two year old with a lisp") so it's not really very usable.
I love the keyless entry and starter. We can open the door and drive off without taking the key out of my pocket or Michelle's purse. I thought it was kind of a gimmick, but I love it. I wish I bought this option on my other car.
I know these features aren't really unique to the Prius, but this is the first car we've that had all the gadgets. Besides, the car just feels like a high-tech golf cart.
However, the best feature is the eco-smug feeling you get when you drive past an SUV.