Guess Which One Of These Cars is the Most Aerodynamic...

Nice post. You beat me to the point...people love a single number, but frontal area is a king, and never published.

Also, there is a large element of drag with tires/wheels...a key reason I've been babbling on for years about minivans being a better vehicle for families than SUV's. I find the lack of hybrid and/or diesel minivans especially frustrating.

the S class cannot have a cd of .25. thats impossible. the LS460 has one of .27 and i believe its best in class

Good post Greenplease, one point most dont get about the Prius' ugly appearance is the advantage of increased interior volume in a small package. It's what makes the minivan so ugly, but gives it massive cargo space.

A quick search at http://www.absoluteastronomy.com/topics/Drag_coefficienyielded:
0.27 - Infiniti G35 Infiniti G35, 2002
0.27 - Mercedes-Benz W203 Mercedes-Benz W203, 2001 - 2007
and
0.26 - Lexus LS 430 Lexus LS, 2001
0.26 - Mercedes-Benz W221 S-Class Mercedes-Benz W221, 2006

So - No - not 0.25

"Drag coefficient" is after all just a coefficient.
Front wind resistance = frontal area x drag coefficient
The frontal area of a Prius is almost like a square box to maximize interior space and reduce weight. It is very difficult to reduce coefficient when you have to work from a boxy shape.
The sedans listed (including Lexus LS) has a wider bottom and narrower top side. Not boxy. It is easier to reduce coefficient from that sort of shapes.

Please name a minivan that has sub 0.3 coefficient?
Modern CUVs (frontal area more boxy than sedans) have coefficients in the range of 0.34 to 0.38. That gives you an idea that making is below 0.3 is tough. On top of that, the length of vehicle also impacts the coefficient. Longer vehicles have lower coefficients (assume everything else being equal). As a result, you get the Prius shape (similar to the new Honda Insight)