Hm. That's very difficult. Because the price of the computer alone is just the beginning. You need an antivirus and antispyware program, a warranty, a good case or carrier, software programs (since computers these days don't come with Word, and you'll need that for school. the microsoft office package is at least $400), and backup, such as an external hard drive (trust me, you WANT this!!), zip drive (many call it junk drive).. and those are just the necessities.
If you get a notebook, which are the tiny ones with an annoyingly tiny keyboard, you may need a separate disc writer because many notebooks don't have them built in. Without this, you can't use DVD's or CD's.
If you are enrolled in any school, you can get discounts. Also, you may find a good deal through your college but do your shopping around first. Remember, people promise "big deals" when they're actually dropped inflation. Pooey deals.
For your budget, you're best bet is to buy used. Or better YET buy from a friend who is upgrading. Ask around, but make sure to be thorough in your questions as to how they used it and what problems they've had.
You know how it is in looking up colleges. You have to account EVERY possible fee and charge. Do the same here. Do your research and with some work, you'll save yourself some good money.
Last tip: for great consumer reviews, look at
The Consumerist. They have info about nearly every computer listed in your poll, and if they don't, that could be a good or bad sign. lol You choose. They also have news reports about computers and companies, with comments and more reviews below each one. ALSO each morning they post a list of "morning buys" which always include electronic sales. Watch them for a while or look at the archives and you'll catch onto a trend with certain stores. It's a free site, and more informing, unlike angie's list.