To be honest, look at the cost of the car, vs the gas mileage difference and figure out which one will be the best deal. In looking at the additional cost of hybrids, you may not see a return on the extra cost for 4-8 years over a car that gets slightly less mileage. Plus, the cost to repair a hybrid is going to be much more expensive than say a bonneville.
Say you are looking at the Nissan Altima Hybrid, which gets 40mpg. On a 400 mile trip, you use 10 gallons of gas, at $4.19 a gallon, that'* $41.90 to fill it.
Now lets say you go for the 04 SE, which gets 28-30 mpg (we'll use the lower one) so going 400 miles will be 14.23 gallons, which is $59.86.
The difference is $17.96 per 400 miles. Assuming that you drive the average 12000 miles a year, that would equate to spending $538.80 extra on the cost of gas per year. Now, looking at the difference in price, you can figure out how long it would be til you evened the cost out.
Now, just be aware that other factors, like resale, maintenance, warranties, and such also play a factor but for strictly gas mileage, it isn't always the best choice (unless you are going from a 13mpg truck/SUV to a 38-45 mpg compact/hybrid
2007 Saturn Aura XR | 1970 Chevy Blazer 4x4 | 1970 GMC 3/4 Suburban 4x4