Laptop for university

hi people!
I'm a snr in high school, for 5 year, I've been carrying my laptop with me to school, for taking notes, working on projects, and just doing stuff.

I'm so use to having one next all the time, but its really killing my shoulders! So, im thinking about buying a new one before i leave for college.
My plan is to use my MacBook as a desktop, and get a smaller, lighter laptop to carry around.
I don't really care if its not mac, I just need something that can do simple things like simple word documents, download from SD and CF cards on the road, e-mail, net, and sometimes dvds. And of course cheap.

any recommendations?