Where do you store you fuel jerry cans?

[OverlandG-wagon]

I am heading out on a long trip and would like to carry some additional fuel. Any preferences as to where tou mount jerry cans? Roof or rear door? Pros and Cons?

 

[V8Runner]

I keep mine on the roof. My though is that it is harder to hit them up there whereas in the rear you can accidentally back into something or you may get rear ended

 

[Frontier4x4]

It must be a pain to lift them up there though. I would mount them in the rear