For all of you macbook and macbook pro owners out there, what kind of actual battery life can one expect out of the machines? I know the apple website lists specs of what the machine SHOULD get, but what kind of battery life do these machines REALLY get? I am still going back and forth on which system I should buy and believe it or not, the battery life does make a big difference in my decision...I am on the road a lot and I dont always have a place to plug in my notebook! If you have actual average hours of use specs, that would be great! Thanks!!