I usually name a character after what I plan to do with it.
For example, if I'm playing a challenge kind of game, I may name something similar to the type of challenge. (Example: When doing my LightBringer challenge (wield two lanterns as weapons) I'll name myself something like Edison, Glowrod, etc. If I'm doing a Metal Gear Solid esque challenge (leave no corpse out in the open, put them in rooms and close the doors. Leave nothing behind that could show you were ever there. There are so many ways this can kill you) I'll probably name myself Solid Snake, Liquid Snake, Gaseous Snake, Plasma Snake, you get the idea.
Id I'm just playing for fun, it's Vault Dweller and his faithful pooch Dogmeat, all the way.