Is that a SERIOUS question? If so, here is the serious answer:

The answer is pollution right now. Until the "clean diesel" engines make it to the USA, with Ultra Low Sulfur Diesel available at 100% of the USA gas stations which sell diesel, and the advanced technology diesel Particulate Matter filters in place, and ALL 50 states allowing the sale of "new" diesel passenger cars, then diesel is far more polluting than hybrids.

My dream car is a 5-passenger sedan, DIESEL ELECTRIC PLUG-IN hybrid which gets 80 MPG in hybrid mode and gets about 60 miles in EV mode before starting the engine.

For less than $35,000. I'd trade my TCH on that car TODAY.