Oh, I'm a huge Firefly fan. I discovered it after the fact, too. Bought the boxset on the basis of seeing two episodes on the SciFi channel.
Have to say that the last time I went looking for fanfic it was to find the quality was poor at best. I don't think I ever did find anything worth reading.
Mind you, that was a fair time back, so things could have improved by now.
LabRat