There's one call that Clark has taken on the air about 60 times over the years, and he's never been able to answer it convincingly: Is it worth it to pay the extra bucks to buy a hybrid just to pay less in gas every week? Now Edmunds.com has done a cost analysis of some of the top hybrid models. Their research indicates how much longer it takes to get a return on investment if you buy the hybrid versions of any cars in the study. It's the Ford Escape that gives you the quickest payback -- owners will break even at around 3 years. The Honda Civic and the Mercury Mariner tie at No. 2. The Saturn Vue checks in at No. 3, allowing owners to break even in 4.8 years. Keep in mind that any hybrid offering return on investment in under five years is a smart buy. On the other end of the spectrum, the Toyota Highlander takes 11 years before you break even and the Camry will take you 12 years. And what about the Prius? Because there's no exact gas-engine equivalent, Edmunds looked at the Prius vs. Corolla. Turns out it will take you a whopping 13.6 years to get payback if you only drive your Prius 15,000 miles/year! So Toyota -- the greenest of all the automakers -- actually does not give you good payback on your hybrid-purchasing dollar. Clark advises people to only buy a Toyota hybrid if they're doing it because of deeply held environmental beliefs.