I am, first and foremost, a storyteller. That means breaking out a notebook (sometimes a paper one, sometimes a computer) and getting the story down in writing. While I love the advantages there are with using screenwriting software like Final Draft, one can't get past the need to see a hardcopy of a screenplay in one's own hands.
I've a bit of freelance journalism and editorial writing for local periodicals but to feed the soul, I have to create an entire universe. Sometimes that universe is no bigger than a single room, but it's up to me to populate it with interesting characters.
I try not to limit myself to any particular genre. I will write whatever I feel inspired to write. One story might be science fiction, another an intimate portrait of a disfunctional family. No matter what the context of the story that I am writing, it isn't worth doing if my characters have no depth to them.
One of the most common themes that comes up in my conversations with other filmmakers is the need for a good story above all else. I follow that with the need for characters that you can care about. If the character is dispicable and not the type of person you would want to know in real life but you care about him anyway then you've got a real winner.
My writing started in the form of short stories. As I matured and started to take more time with my story and character development, these short stories grew into novelas. I used to worry, as I first wrote these stories, about someone buying the rights to them and changing them beyond recognition. I still get pissed off when I see a great book turned into a lousy movie. But I came to an understanding that one follows much different rules when telling a story on a movie screen as compared to the warm pages of a novel.
The novelist has the luxury of taking his audience into the very minds of his characters. The novelist can describe, in minute detail, an action that in reality would take place in the briefest of moments.
At the same time, the filmmaker can paint on the screen an action or transition that cannot truly be done justice if only portayed through the written word.
Changes simply must be made when adapting a story from the book to the screen. But I feel a lot better about making changes to my own stories than putting it into the hands of a writer who doesn't know the characters or plot as well as I do.