Excellent post--I write (and have published poetry), and dabbled in playwriting which I loved (even harder to get produced than published), and am currently working on a vampire novel which grew out of one of my fan fics, but I became totally hooked on fanfic late in life because, in part, of the feedback.

Crack cocaine!

(I've published academic stuff as well.)

Writing for publication is something I do, but I don't see it as hostile to or keeping me from writing fanfic (different purpose, audience).

I always love confounding those people who express the idea that fanfic writers are all losers who cannot write anything else.

Just as I always enjoy confounding my college students who think that people who read sf are stupid and weird.

*heh*