If the character is male, Mike or Micheal, depending on the number of letters/symbols I'm allowed.
If the character is female, it depends on whether the character is meant to represent me or is a character in her own right. I always use Mishi for pokemon games, for instance, but I named my female Shepards Katherine and Miriam.
But if the character already has a canon name and I don't dislike it, I generally go with their default name.
But in titles where I can customize my characters' appearance, I have been known to be immature. I have an Orlesian Warden-Commander named Cyrano (with all the nose sliders up to maximum size), and I had a Runes of Magic character named Torpedotits (guess why).