I think the cat picks the name. Grey Girl was named Ashes at the shelter but she responded when I would coo, "Oh, you're my pretty grey girl. I love my grey girl" so it stuck.

Eepie was named Angel at first because I love angels but she eeped so much as a kitten (eep! eep!) that we got to calling her Eepie.

My sister's new kitten, Oliver, was a stray she took in. She called him Little Shadow just to call him something until he got a good name. (She had a large black cat named Shadow and Oliver looks almost just like him.) The name Oliver came about because every time she would feed him, he'd ask for more!