When i was recently in california i noticed alot of hybrid cars, which is something that has not realy taken off here in the UK.
Every hire car i have had in the US has had a large engine (by european standards) been an automatic and run on petrol, I seen next to zero diesel cars, and when filling up a car in the states i hardly ever seen a diesel pump on the forecourt.
I think becuase petrol is so cheap in the USA there is far less concern about fuel economy. I was only paying about $4.5 for a US gallon.
Currently in the UK hybrid cars cost alot more than diesel alternatives, have lower MPG, and far less choice of cars, prius is the only one commonly seen, where as almost every car maker has a couple of diesel versions of there cars. Infact i think the biggest reason people currently buy hybrids is to be Greener.
We now have a few electic cars being sold here, though it may be a while before the running ost per mile is proven.