Computer hardware is complex, and there's an endless array of combinations available. Fortunately, students have relatively simple needs, and this takes a lot of confusion out of picking the right components.
Most students need a machine that can browse the web, open documents and spreadsheets, and perhaps edit the occasional image. Students may also want to play games on their machine, particularly those in college, since the dorms and cramped apartments occupied by undergrads aren't great homes for wide-screen televisions and game consoles.
Currently there are two options that stand out. Intel's second-generation Core i3 and i5 processors are one solution, and they provide the best performance of any mobile dual-core currently available. Documents will open quickly, web browsing will be a snap, and programs like Photoshop will also respond with speed. Gaming is still lackluster if these processors are not paired with an Nvidia or AMD graphics solution, but some 3D games will run at acceptable framerates. You'll also be able to watch HD video without issue.
Another option is the recently announced AMD Fusion A-Series processors. These have much slower processor performance than Intel's Core i3 and i5, but they offer an integrated AMD Radeon GPU that is superior to what is bundled on Intel's products. If you'd like to play games on your laptop, look for a Fusion A6 or A8 processor. These can play most modern 3D games. Again, HD video is easily handled.
You'll also want to make sure you buy a laptop with at least four gigabytes of RAM and a 500GB hard drive. These are not hard to find, however, even in budget laptops.