You go, girl! Personally, I think that Mary Sues should only exist in badfic. Frankly, it's hard to write fanfic for any length of time without introducing new characters. I mean, come on. And even though some of my favorite original characters (Billie from "True Nature" comes loudly to mind) could easily be called Mary Sues, I like to think they are fun and complex and at least interesting to read.

I have much more problem with badfic and bad characterization than with Mary Sues, personally.