Although I don't personally write fan fiction, I read a great deal of HP fan fiction. My "favorite stories" list is primarily stories that are completed. Check under the "favorite authors" list for some excellent unfinished stories that are currently in-process (that is, not abandoned).

I mainly like Snape-centric stories, angst, hurt-comfort. My personal "take" on the character is more akin to that of Whitehound, duj, or possibly E.M.Snape. I post regularly on the HP Lexicon Forum.

I have a particular thing I'd love to see in a future story. Practically all of the male/male Snape friendships (non slash) that I've found in fanfic stories are with Dumbledore in a father/mentorship role or with Lupin. But the real men I know who have that kind of biting acerbic personality sometimes find close peer friendships with similarly acerbic people. In my observation, they start verbally feeding off of each other, constantly testing one another's wit and ability to throw verbal punches. I have yet to see that kind of relationship portrayed in a Snape story. But I doubt if anyone could write it who had not actually seen that kind of relationship in real life. Still, if someone does understand that kind of friendship, I think it would make an interesting way to explore Snape.