This is a fairly inexpensive add-on. Be sure to specify powered speakers. Some cheap speakers run only on batteries. Plus, powered speakers are shielded magnetically so they don't affect the rest of the computer. 16-bit wave sound with powered speakers.
Most new computers come with an operating system, but make sure.
Windows 98 is highly recommended. The campus computing centers provide great support and are geared more towards Win98 than anything else. Windows NT is not for a personal computer, and Linux is definitely out. Network All of the dorm rooms are wired so that your computer can be networked to the rest of the campus and the outside world. There are printers in most of the dorms, but if you would like one closer, consider the Epson Color Stylus 400.