May I recommend going into a specialist computer store I have found the independant ones very good. Not the large chains where a gormless teenager on a saturday job stares at you like you have no idea what you are talking about. I got mine in a small business, they make up a laptop to your specifications so will be much more ready to listen to exactly what you want and avoid all the things you dont need on it so you could actually tailor it to your own needs.
They are often very reasonable as well. No harm in ringing for a quote and dont be shy in telling them youre a student and your budget is only...Also tell them you're ringing around. You'd be surprised what a little competition can do to prices.
Anyway thats what id recommend. Get the yellow pages out!