I would disagree that Cruise is teh most economincal though. The cars tend to 'over' accelerate to keep the speed, also going up hill you can let a car drop 5 or so mph without any loss in time but a considerable saving on fuel, Cruise will keep teh speed irrespective of how hard it has to accelerate.
I remember a friend and I driving to see my Sister in Nice on teh cheap. We used to drive in bare feet as it was amazing just how much extra 'feel' it gave you on how much you were using the accelerator(although free wheeling with teh engine switched off down teh alps maybe wasn't that good an idea especially when you get pulled for speeding through a tiny village but thats another story!
)
Actually people like BUsman can be a godsend to fuel economy! Sitting in the slipstream of a coach/wagon saves a load!!!!!