At the request of de_facto_female, a Harry Potter rec:
http://ashwinder.sycophanthex.com/viewstory.php?sid=16178 It's Snape/Hermione and though I haven't read it for ages, I seem to remember enjoying it quite a bit. Beware though, there is more than a little Ron-bashing for those who can't stand that sort of thing. It's AU, I believe from HBP though possibly from DH, and envolves grown-up Hermione as a St. Mungos healer. So no school based argy-bargy.
I also highly reccomend this:
http://mhalachaiswords.livejournal.com/188552.html Which is a HP/Stargate Atlantis crossover which works on the assumption that John Shepperd and Harry Potter are the same person. Sounds odd. Works. As does the sequel. As, in fact, do all the author's fics. I'm kinda assuming everyone has heard of Mhalachai, but if you haven't then waste no time in going over to her LJ and checking out all her fics, especially her amazing crossovers. I warn you that you will be sucked in. I started watching the Gilmore Girls simply so that I could read one of her crossovers without getting horribly confused, and now I'm addicted.
Anyway, gotta go as I'm clearing out my desk to start a new job on monday at the Natural History Museum!