Most of my computers derive their names from characters in books I have read. In the case of several clusters I administer, the machines are named after wizards in a variety of fantasy novels, from the well-known Merlin to more ambiguous and less well-known names such as James (Eckert, Baron de Bois de Malencontri et Riveroak).
My primary Lunix Systems server is named Dakar, after the Mad Prophet in Janny Wurts' "Wars of Light and Shadow" series. It fit the wizard requirement and also serves to ward off misfortune through wry humor, or so I like to think.
The secondary DNS and MX server for Lunix Systems, which is hosted in Claire's soap studio, is named gandalf, mostly because it is ancient Sun hardware (a Netra T1 105 at 440MHz, specifically).
Another of my favorite servers is named after Belgarath, from David Eddings' "Belgariad" and "Mallorean" series. A file server (with RAID5 array) I built several years ago now, belgarath has a nice long uptime and almost takes care of itself.
Eve Forward's "Villains by Necessity" briefly features the Gnifty Gnomes, a chronically cheerful town of little people whose merrymaking is cut, trampled, and generally flattened short. They provide the naming scheme for this web site.