If its something private, I just do my initials (old habits die hard). If it is something public (online game), I tend to go with "sundin" or "sundin13".
However, lately, I've been trying to RP a little more with my characters. I named my Pokemon X character "Ennis" and dressed her up like Ennis from Baccano! and had a ton of fun, so I'm probably switching to that route now.