One of the many reasons cited for the continued success of the Toyota Prius is its unique styling, which is both aerodynamically-sound and makes the car instantly recognizable as a hybrid. Other automakers have taken the route of adding special badges or modified grilles to their fuel-saving automobiles to help differentiate them from their standard siblings, but sales of these slightly modified hybrids have not taken off like the Prius. While the car's unique shape isn't the only reason the Prius is the best-selling hybrid, it certainly doesn't seem to hurt.
Hyundai is expected to release its first hybrid model in late 2010. The car will be based on the Sonata midsize sedan, but may sport a distinct look to separate it from its non-hybridized sibling. Further, according to Woong-chul Yang, president of R&D for Hyundai-Kia Motors, the Korean automaker "may change the name if the exterior is quite different. People who drive a hybrid like to be differentiated." You don't say.
[Source: Automotive News - sub. req'd]