If you look at interior space, a Prius is closer to a Corolla than it is to a Camry. I compared the Corolla and Prius cost of owernship, and the Corolla was cheaper by far. You would need to drive that Prius for the next 10-15 years just to recover the cost difference. It's also worth noting that the Corolla has a more powerful engine and better performance in every category
I don't disagree with the overall sentiment here, but I think it's just a little off.
2011 Corolla base MSRP $15,900 (132hp 1.8L i4, manual transmission, 104.4' interior volume, 28/35mpg)
2011 Prius base MSRP $22,120 (134hp 1.8L i4 + hybrid, auto transmission, 115.3' interior space, 51/48mpg)
So, the Prius has about the same power, comes with auto (auto adds more to the Corolla cost, though I actually prefer the compacts with manuals anyway), is about 10% larger, and gets dramatically higher fuel economy. The prius is almost 40% more expensive though. There is a bit more standard tech in the Prius just due to the nature of it being a hydrid (LCDs, options, etc). There's also a bit more sound dampening.
For a primarily city driver, at 20k miles a year at $4/gallon gas prices, 28mpg means 714 gallons of fuel used at a cost of $2,856. At 51mpg that drops fuel use to 392 gallons, for a total cost of $1,568. That's a savings of ~$1,300/year, or $6,500 over five years, which is slightly more than the price gap between the vehicles.
Obviously this can swing a bit in either direction. Lower usage and/or lower fuel prices will sway the value a bit closer to the Corolla, and the reverse is also true. If one believes that China/India will continue to put higher and higher demands on world oil production, then it's fair to assume that gas will probably never be much below current prices, and could possibly go a lot higher over the next decade. Swings like that put a premium on the resale values of high fuel economy vehicles.
A lot to think about for sure, but it's good to use hard data for the calculations.
Of course battery replacement costs should be taken into account for the hybrids, but I think the Prius is good for at least 5 years/100k as proven by the huge fleet of them already far past that on stock batteries.