In retirement we drive so little, perhaps 4000 miles/year, so the gas savings will take a very long time to offset the higher cost of a hybrid. A vehicle getting 40mpg burns 100 gal/yr, while one that gets 25mpg burns 160 gallons. At $5/gal, that's $300/yr differential for us.
I would consider a hybrid if its premium over a regular car is less than $5K. And then, I would make sure that the battery has a good reputation of not failing too early. Of course someone who drives a lot more will have a different perspective.
If someone has a class C RV that can get me 15 mpg instead of the 8.5-9.5 I am getting now, I would be very interested. Oh, they have diesel class C's that do that well, but I would have to drive 100K miles to save 4400 gallons or $22K at $5/gal. And given that diesel fuel costs more than gasoline, and a diesel engine costs more to maintain, I will never recoup the purchase differential, which can be as high as $30K to $40K.
In the 5 years I have had my motorhome, and taking long trips every year (as long as 2 months) as I have done, I have driven only 30K miles.