My previous alias online was Lightning and you only find that associated with me here on PC and at websites where you can't change your name. Otherwise, I've fully switched over the Cherrim. Generally, if you see that username in use, it's me. It's not super original since it's a Pokemon name and all but that doesn't bother me much at all. Better than people assuming you picked the name for a Final Fantasy character you don't even like. :P
If Cherrim is taken, I default to Ceriflor (its French name) or Whimsicott. If everything's taken I just start trying variations and the like while whining that I don't have any more creative ideas and why didn't I find this site sooner to secure my identity and so on.