serious engineering schools do not allow graphing calculators in exams.

this is not generally true. unless the class is specifically to teach things the graphing calculator does automatically.
<< NC State engineering department alumnus
i understand that there are other contributing factors, but don't let state's "requirement" to have a laptop force you into it. the only class that ever required a laptop i had was a graphic design elective, and at that time (4 years ago) there was also a non-laptop section for the class. as you said, the computer-oriented classes pretty much all take place in the linux computer labs. you can remote into them, so you don't need a dual-boot. they have no way to enforce the laptop requirement that i know of, and i highly doubt you'll run across a professor who would throw a fit if you don't have one.
if i were to do it again, i would want a powerful desktop in my dorm/apartment as my primary work/gaming PC, and a relatively cheap laptop to carry around for use in class and the library and whatnot. you will use your laptop in class FAR less than you are thinking you will now. funnily enough, they are most useful in liberal arts classes where you can actually type your notes. unless you're rediculously skilled at LATEX or have a tablet, you're going to want to hand write your engineering and math notes. i should note that my laptop did need to have discrete graphics for that one required class to run solidworks in any kind of meaningful way. i wouldn't want to see how that performed on integrated. let me just say, no matter how careful you are with it, if you carry a laptop around regularly, it WILL get worn and abused, no matter how tough the manufacture claims it to be.
as for support, State has a tech help center. i THINK it is open to all students, but you should check on that. you might consider buying from the bookstore and you don't have to worry about crappy support. you won't be able to get a very cheap one from there, but from what i remember their accidental damage coverage is WAY cheaper than a retail store, and worth it. if you never end up needing it, you can always "accidentally" drop it off the 4th floor or throw up on it.
edit: one final note. just to re-iterate what others have already said, no matter how powerful of a laptop you get, it won't last. mine was relatively top-end upon entering school. by junior year it was getting annoying, and by graduation i wanted to destroy the ****er. i actually shot it (with an airsoft gun) right before the coverage expired to blow some steam. all it is used for now is watching movies while laying back in bed, and as my sacrificial porn browsing computer.
