i'm 22 and have only owned diesel vehicles for my entire driving career... a '91 chevy truck, '94 chevy suburban, and then a 2000 volkswagen jetta tdi, which i still drive currently. i love the gas mileage i get with my jetta (about 43/48 mpg city/hwy) and its quiet enough that many people don't even know it's a diesel.
there aren't many choices for diesel vehicles currently, especially if you want a car and not an suv or truck, but i think more and more manufacturers will convert their european diesel models and bring them to the US within the next 10 years because the demand for them is going up as gasoline prices increase.
the initial investment is a little more, but the reliability and money you'll save with the gas mileage is far worth it, especially if you drive it for an extended period of time.
here are two good articles about diesel engines and the future of diesel cars/fuels in the US:
http://www.edmunds.com/advice/specia...8/article.html
http://www.eere.energy.gov/vehiclesa...sel_engine.pdf
and here's a website with loads of information regarding VW's TDI vehicles:
http://www.tdiclub.com