If won't come as a surprise that servers usually come with a lot of ports, far more than any desktop PCs you will come across, making them ideal for DIY projects like Digital Video Recorders (DVR) or home servers.
A lot of them will carry legacy ports (VGA, Serial and PS/2) with plenty of USB ports (about a dozen) both in front of and behind the chassis. Some, like Dell's T20, have some surprising combinations including a pair of DisplayPort ports, a connector usually found on workstations costing a thousand pounds or more.
