An internal CD-Rom drive is recommended. A CD-Rom drive either external or internal can be also added to a system without one. For inside your computer, you will need a sound board or card to take full advantage of the multimedia capabilities of CD-Rom software. Speakers are also necessary. Choosing these speakers is much like selecting them for home audio equipment.
Speakers are probably less than ideal for a library setting.
As an option you may want to use headphones instead. These will actually plug into the sound board not the CD-Rom drive, so be sure your sound board has a jack for headphones. Workstations are also now sold complete with these capabilites pre-installed at attractive prices. Unless you are very experienced or have access to someone with experience upgrading computer equipment, have your vendor pre-install any multimedia options. You're on your own here.