My first cat (age 7) was Shadow because she was a black cat.
My next cat (age 15) was Pixel, whom I named after the cat from Heinlein's Future History mythos.
My Malti-poo (born 2005 to my parents' dogs) is Voldemort ... his mommy was inbred, his father was under a spell (well, hormones), he wasn't supposed to be born, and he looked like a little white slug. And he's tried killing my mother twice (tripping her).
Just after Voldemort, my ex-husband acquired a Manx cat that had huge ears and a sharp face, so his name had to be Dobby. (Dobby died of feline leukemia about a year later.)
In 2007 was the acquisition of a Main Coon/Calico we named Aphra Behn (the 18th century essayist and smut writer). The ex-husband got her in the divorce.
It usually takes me a day or two to name a pet, so it usually turns into "What am I currently obsessed about and does any part of it fit the new baby's personality?" By that reasoning, Aphra's name should have been Tardis (I was in the middle of an original Doctor Who fanfic writing craze), but I decided to go with something more classical - and she was such a dainty thing, too.