I tend to write in third person, past tense, because it seems more professional to me, though I may throw in present tense every once in awhile for certain scenes.
I like using third person because I strive to show things like emotions through inferential cues like body language and facial expression, I somehow think it a bit more .. challenging than simply telling the audience what the character is feeling. It also more easily allows for scenes with no characters in them, like interludes, than first person.