I like hybrids, yet they have one problem which is significant, especially here in Germany with the Autobahn: They only work at low speed. The average traveling speed on the Autobahn is between 80 and 100 mph, where no electric component of the hybrid engine is working, only the fuel powered parts...so the fuel consumption shoots up rapidly. The Diesel is very economic in every situation.
There's even a Volkswagen (LUPO 3L), which is not offered in the states, yet in Germany that gets 80mpg...and it's not a hybrid, it's a Diesel.
Yet, I believe that hybrids will be the future if Mercedes fails to get the Diesel going in the states (as they plan on doing with the 320 CDI in the R-Class/420 CDI in the new G-Class). The Diesel is just too dirty/requires a lot of cleaning. Actually, the Lexus Diesel is the cleanest in the world because it has an additional filter...yet, all that stuff is very expensive, even in mass production. In the long run a clean hybrid might be cheaper to produce.