1. Its a much better city car than highway cruiser - so if your usage is entirely highway, there are better choices.
2. The fuel savings are unlikely to offset the increased purchase cost unless fuel costs rise, you drive many miles and you keep the car for a very long time.
3. The "green" statement made by owning one is more symbolic than real if you consider the environmental costs of the mining for the minerals used to construct the batteries, the smelting and other processing of those minerals (nickel and cadmium) and the transportation of electrical system materials.
I don't discourage people from buying Priuses. For stop & go city drivers, it can be a good choice. I just have to laugh at the intellectual dishonesty of calling the car "green". That's just marketing.