First Person?

Many writers of Urban Fantasy choose to write in the first person.  In fact, I can say that I can almost count the number of UF books I’ve read that break this format on one hand.

Why is that?  What is it about Urban Fantasy that leads us to exploring it through the eyes of a single narrator?

Furthermore, is it necessary?  I wrote my first novel (and a half) in third person.  I wrote it that way mostly by accident.  When I started writing, it all came out of a scene I envisioned in my mind.  The narrator of that scene was omniscient; all the better to see all the details I imagined and there was no main character as of yet.  When I finished, I had introduced a handful of characters, three of which had an ill-defined, but powerful, conflict I wanted to explore in more detail.

That’s where my novel came from.  Unfortunately, in order to establish the setting/characters/etc, I ended up writing a book that ended up introducing the principle players in an earlier conflict, one that set the stage for the one that has already occurred by the time of that initial scene.  But it was so much fun, and I enjoyed the characters so much, I didn’t mind.

Now, there is that little doubtful voice that is making me wonder if I should rewrite the whole thing from the main character’s perspective in first person.  I’m wondering if third person might be a barrier to finding an agent, since the majority of these books are in a different format.

Any thoughts?