Before heading out to your favorite computer superstore to make your purchase, check out MakeUseOf.com's Laptop Buying Guide 2011. The Guide can be downloaded in .pdf format or read on Scribd.
Also remember that many manufacturers offer education pricing for students and educators. For example, Apple usually sells their white Macbooks for $999, but students can buy the same Macbook for $899 when purchasing through the Education store. HP and Dell offer similar educational discounts. Additionally, see if your college offers special student pricing. This information can usually be found on the college web site.
One more tip . . . don't buy a laptop bag or backpack until AFTER you choose a laptop! Measure your laptop and then choose your bag; not all backpacks can accommodate the widescreen laptops.