Just one-- nonfiction.
When it comes to fiction, anything I like to read, I'd like to write (there are many genres I like that I'm very bad at writing-- romance, horror, mystery-- but I still want to write them).
Nonfiction, however...I love a good article or academic paper, but I wouldn't want to spend my life writing them. ^^; Most of what I write on a day-to-day basis is opinions, observations, interpretations-- not facts. I never feel like I'm enough of an authority on anything to write something that's purely educational, and no amount of research will help me feel more sure of myself. Usually it only serves to reinforce how ignorant I feel...
Saying this makes me feel like I'm working in the wrong field. ^^; I dunno, maybe someday I'll help author a research paper and get over this imposter-syndrome thing, but until then...I'd rather let other people be the 'experts'.