What happens is if you double the battery life, to reduce costs they will halve the battery size. The net result is that I see all laptops to fall into two groups of hours. The portables tend to group around 4 hours of battery time. The desktop replacements average lower towards 2 hours.
You can push the battery time up by opting for more cells in the battery and asking how many Ah (AmpHours) you can get.
PCe eats away at battery life, DDR2 should help. I'm loooking at some of the newer sonoma models that have been released and most have lower battery life.
For someone who values battery life, is Sonoma a good thing?