Here at work, one of my projects uses names from the Potterverse (hufflepuff, etc). Another uses TV robot names (twiki, rosy, bender). A third uses imaginary animals (phoenix, griffin).

At home right now we use metals (aluminum, titanium, magnesium). I wouldn't give a new computer the same name as its predecessor because I've got a full backup of every computer I've had on my RAID, and I want to be able to tell them apart.