Originally Posted by DrD123
Very true - folks get hung up on a single number, without considering the entire package - taking the VW as the example, the Jetta SE is $19k and gets 26/36 mpg (city/hwy) while the TDI is $23.2 and gets 30/42 mpg. So 15% better city 16% better hwy mpg, but the vehicle costs around $4k more and you pay more for fuel (if diesel is 21% more expensive, while you get more miles per gallon of diesel, you are spending more $/mile with the diesel, plus as a bonus you got to pay $4k for the privilege!)
When diesel was cheaper or close to the price of gas, it made sense - nowadays, not so much. Where diesel does make sense is for torque - so if you are going to be towing, it's the engine to get (which is also why diesels are so popular for trucks) - just look at the Jetta 170hp/184 ft-lbs for the gas and 140hp/236 ft-lbs for the diesel.
You failed to take resale value into account. You recoup a large chunk of your upfront cost when you sell the TDI, as they depreciate much slower than the gas version cars. Also, TDI models come with more options than the gas model... almost $2k more of stuff, so the difference becomes negligeable. Throw in the fuels savings (my TDI averaged 8% higher than sticker mpgs), and the diesel makes more sense. I bought mine when there was a $1200 tax credit as well. It would be much more of a wash now...