I'm fully aware that the Prius isn't an all-win proposition in terms of cost, fuel efficiency, and environmental impact. If gas prices are low (<$2/gallon), it is likely that most economy cars will be cheaper to buy than the Prius. Plus, you definitely pay a premium to drive the very in-demand Prius.

I bought the car because I plan to drive it until it dies, and it's upscale enough to drive even at a significantly higher income bracket without sticking out like a sore thumb (as opposed to my other 2 oldie budget vehicles) - this was actually perhaps the most important reason I bought it. I like the "green" motivation as well - even though it's debateable how green the Prius is, supporting cars and technology that move in this direction is a way I'd rather spend my dollars rather than buying more features that I don't really use in a regular vehicle.

Ironically, much less justification and criticism gets sent toward folks who drive $40k+ luxury and sports cars, even though with those vehicles you're really paying tens of thousands for style points alone. I find it ironic that folks who criticize the Prius as being expensive often have very little to say about Infinitis BMWs and Mercedes, all of which are fine,but expensive cars $10k+ over the Prius, and offer mostly luxury nonessential features at a huge premium.

I actually looked at ZipCars here as well - but they're really expensive! It was actually significantly less expensive to just do a standard car rental for a full day than to try to rent by the hour with Zipcar.

But despite not caring much about the long-term economic sense of it in my case, I would definitely bet that in the upcoming decade, you can expect significant increases in gas prices. To $4 and well beyond that. With China & India's rise, increasingly limited world fuel resources, and more power-hungry technologies, even political pressure won't be enough to continue to subsidize our US cheap oil habit. Keep in mind that European gas, which is more fairly priced than ours, is well over $6 per gallon in many countries - our prices are artificially low because of the political danger of being thought of as supporting a gasoline tax. In a sense, buying a Prius can also be thought of as "insurance" against these big (inevitable) price increases, and will thus make the car's relative value increase as gas prices go up. That's also a pretty compelling reason for me as well to justify paying a premium on for a car I intend to drive for 7-10+ years.

Also - used Priuses here in SoCal are expensive. 2006 models were going at only $3000 less than a brand new similarly equipped 2010 model. These cars are in-demand, and hold their value extremely well. I was hoping to see some of those 20% off the new price for a 2008 model, but there were no such deals whatsoever that I could easily find. 2009 models were selling at 90-95% of similar 2010 models.

But still - like I said - I ride my bike more than I drive my car. That's a complete win-win situation for everyone. By a LOT. I hope it stays that way!