I haven't used any original charcters in my fics yet, but
a) I am working on one that would probably require some; and
b) I don't only write fanfic

And so when I do need a name, for a first name I just use a name I encountered on TV or in school, and for a surname I just use a fairly common one, like Jones or Smith or Black. Most of the time. I voted C because it was the closest one.

Julie smile

Mulder: Imagine if you could come back and take out five people who had caused you to suffer. Who would they be?
Scully: I only get five?
Mulder: I remembered your birthday this year, didn't I, Scully?

(The X-Files)