Bad Wolf, that's a great idea.
A colleague of mine names his servers after celestial bodies (planets, moons, and lately constellations). Io, Europa, Ganymede, Kalyke, etc. This is a pretty limitless way to go, but I find some names difficult to remember and hard for some people to spell (Kalyke for example).
Personally, my systems simply have female people names (Cammy, Kelly, Felicia, Erica, Emily, etc.) which should never run out of options.
I make a point to use names that aren't of any women I know, to avoid causing ideas or jealousy in my wife. She's still jealous of Cammy, my workstation, but only because it's better than hers!