I graduated from a University in CS last year and I don't understand your need for such long battery life.
Many of the rooms had outlets handy, some at every chair, others just a few at choice spots where all the nerds camped out. Do you really anticipate that you will be in class 8 hours straight? No breaks between classes to charge your laptop and refuel yourself? Is this also needed for your commute to and from school (perhaps while on a train or bus)? If you are constantly in large rooms (lecture halls?), they typically had outlets underneath every seat.
I went through senior year on an Asus Eee PC 900 that lasted 2 hours at the most, but I typically plugged in seeing as there were outlets everywhere. Usually the rooms without the outlets were the ones that didn't require a computer and the only thing people did on computers was play FarmVille/read Slashdot/troll Digg/whatever instead of paying active attention. This was also my primary laptop and I used it to program my Senior Design project in (not something I would recommend on an Eee PC 900).
I am not putting your want/need for this amount of battery down, but I'm not following why its so important in a laptop making decision.