I need a new computer for grad school. My current one is five years old, and while it still runs well enough for "entertainment purposes" (ie, the Internet), it will probably not handle the statistics programs I need it to without having a conniption.

Computer shopping is driving me up the wall. I've been mostly looking at Dell because there's a AAA-member discount (and even barring that, the university discount gets me ~12% off some systems). Unfortunately, this discount limits my options, otherwise I'd have had this sorted out. I have it down to three systems:

System 1: Cheaper (like $200 cheaper.) Nicer display, keyboard set up the same as a desktop. Tray-type CD/DVD drive. Better battery life.

System 2: Backlit keyboard (Good for nightowls like me/darkened classrooms). Thinner and lighter, though slightly bigger. Slot load optical drive. Shorter battery life. Bigger hard drive.
(Both of them have the same processor.)

System 3: Most expensive (by about $60), but this is the option with the better processor (2.5GHz vs. 2.3), 8GB RAM (vs. 6), bigger hard drive (though I'm planning on getting an external hard drive anyway). HD display. This is one of the "performance" laptops, and unless I develop a gaming habit, it may be more computer than I need.

Any advice? I need to be able to run giant Powerpoint presentations (that's what they use instead of textbooks) as well as the statistics programs they want us to use. None of these have a Blu-ray drive, which is something DBF is concerned about. (He's looking at other computers for me as well.)