Your best bet is to buy the most power you can afford. Go for a laptop with a Pentium II processor. RAM is like a workbench for your laptop's brain with the software being the power tools. The bigger the workbench the more tools your brain can work with at one time, and the more it can do for you. Get at least 32 megabytes of memory.
Many models now come with CD-ROM drives.
Make sure it's 16-speed or faster. A laptop needs either an Ethernet connection or a modem to talk to computers hooked together all over the world. Most colleges provide an Ethernet jack in the residence hall rooms for each student. If this isn't available at your college then get the fastest modem you can afford. Lithium Ion batteries are more expensive, but last longer.