I stumbled into on-line fan fiction when I found ff.net in October 2008.
Most of my stories to date have involved NCIS, particularly the Gibbs and DiNozzo dynamic and tend to be narrated/ written from a Tony point of view. Recently, however, I've been re-watching Star Trek: Enterprise and have been rather taken by the friendship and interactions between Archer, Tucker and Reed.
I'm a bit of an angst fan. I do like to read a good case/sci-fi action fic and I'm also partial to a bit of humour and the odd mirror universe fic.
I have an NCIS C2 over on ff.net called 'Little Gems - the hidden case files'. All the fics in there are under 10,000 words and I recommend all of them. However, there are some fantastic stories on lj that just can't be posted on ff.net hence I come over here to read and rec those.