USB and FireWire
Unless you're particularly attached to an ancient printer, you need not concern yourself with legacy ports such as serial and parallel connections, though they are still being supported by the majority of today's motherboards. USB has replaced these slower ports for connecting printers and other devices such as digital cameras, MP3 players, and handhelds. Many mice and keyboards also use a USB connection instead of the old PS/2 port. At 480Mbps, the newer USB 2.0 offers 40 times the speed of USB 1.1. With so many USB devices out there, we suggest you settle for a minimum of four USB 2.0 ports, and you shouldn't have to look too hard to find six or eight, with a couple of them conveniently located on the front panel.
FireWire, also referred to as IEEE 1394 and as iLink by Sony, is another popular port for peripherals. The standard was developed by Apple and is used mostly for connecting digital-video camcorders or external hard drives. Not to be outdone by USB 2.0, FireWire recently received an upgrade that doubles the speed to 800Mbps. The two versions are referred to as FireWire 400 and FireWire 800. One FireWire port should do the trick.