Whitey,
Some other questions you will need to ask yourself is
-How long do you plan to own your car?
-Where do you see yourself/relations/Marriage/Kids during the lifetime of the vehicle?
-Will your commute/job change and if so, when?
I ended up with my 2010 Prius because I wanted a car that was reliable with a low cost of ownership. The car gets phenomenal gas mileage (and in your commute, with lower speeds, you should get great MPG’s as well) and is very low cost to maintain. There are no belts on the car to replace (including timing belts = $$$). There are no 15k and 30k expensive services, all services are at 10k and for oil changes. The car has a back seat with legroom suitable for adults (I am 5’9" tall and can sit in the back seat, behind the driver’s seat, with the driver’s seat all the way back and still have 2" in front of my knees). This meant that my kids (9 and 7 at the time) could grow up to be adults (19 and 17) and still have legroom as rear seat passengers.
If you don’t plan on having kids (or more than 1 additional passenger, the C may be the better car. I don’t like how small it is (and this is from someone who drove a 1988 CRX HF), but, then again, I never test drove it.
The plug-in would help your MPG’s, especially if you could plug in at both ends of your commute. There is more than just “monetary” compensation for a Plug-In, you also pollute the air less, and there is value to that (although that value is hard to calculate, thus is often ignored by people who only want to know the Return on Investments). Of course, no one ever talks about the return of investment on leather interiors, upgraded stereos, or V-8 engines either…
Also, with a plug in, you will need a place to plug in (hopefully, you have that ability at your place of residence). You can also get tax credits to offset the cost of purchasing a plug-in, so that may help. It really isn’t a $10,000 difference, because you can’t just compare a Prius C to a Plug in Prius, they are two different cars. Comparing a Prius vs a Plug in Prius, would be a better comparison.
For my commute (30+ miles, one way, mostly (80%) highway, the plug in wouldn’t help too much as I can’t plug in at work. On the weekends, that would be a wildly different story, since most of my weekend trips are short distance “mileage killers”.
Good luck with your decision!