Kiplinger's has a pretty good article on Diesel vehicles and how you can recoup their mileage savings from the upcharge the dealer charges for the diesel engine option quicker than hybrids. I recently had a discussion with a good friend on this exact topic as he was considering purchasing a recently used TDI (diesel) Volkswagen. It makes perfect sense to me. I'd especially like the Mercedes E series diesel. Hey, one can always dream!