So how do you decide to name your party members?

Most of the time if the choice is given, people rename the main character after themselves. And the main female of the story is named after their significant other at the time. And the rest of the characters get named after close friends and family. (most of this being from a guys point of view while playing, except the latter)

So how do you decide what to name your characters, and also the vehicles and ships you get to rename?