I drive a 2006 Jetta TDI w manual trans and love it, I never check the fuel mileage. It's probably mid-30s to 40 in town and up to 50 on the highway. It's just really, really good and I love driving the car.
I don't understand your question/dilemma at all though. You seem to think there is only a 1 mpg difference between driving your car w a lead foot and "like a granny"?
It's probably more like a 10 mpg difference if not more. And the difference in fuel cost between something that gets mid-30s and mid-40s w today's fuel prices is chump change. When I'm deciding whether to take my VW TDI or my 3/4 ton 4x4 to Mammoth and back, that's a difference.
