There are a number of labs on campus, one of which is open 24 hours with ID card swipe access. When the going gets tough at the end of the semester, the Wildman Science Library computer lab is also open 24 hours. If you're the procrastinating type, don't be surprised at the demand for computers at 4 a.m. with finals week fast approaching. For those students who can't focus in the labs, Lilly Library offers laptop computers for checkout. The wireless network is available in most campus houses, academic buildings, both libraries, and even in the Heart (Earlham's central courtyard). High-speed Internet is standard in dorms, and network folders can be conveniently accessed through an FTP address. This means picking up work on a dorm computer that you started in the library is no problem.
Having your own PC gives you more options, but if your system is unreliable, it may be best to leave it behind. Wherever you compose your drafts, free printing will be available in all computer labs. Plenty of students who rely on campus facilities are perfectly successful. Whether the purchase is worth it for you comes down largely to personal preference and flexibility.