I generally read Spuffy fic. I just find Bangel kinda boring. Angel isn't my type, no harm, no foul.
There is so much out there, basically any style and genre so I read whatever I'm in the mood for. I like canon fic, but it doesn't matter to me if it goes off canon either.
What I don't get into are long "out there" fics. I can only suspend disbelief and dwell in the absurd for a certain amount of time, then my attention span runs out. So I only read short fics that really stretch the boundaries...in outer space, body switch, etc. They are fun for an afternoon.
Probably the ones I read most are one's that parallel canon but have a twist to them, or fill in the blanks interestingly.
Some that change one major premise are interesting too. It's a "what if" but not too many "what ifs" for me to be able to follow along. So "what if Spike was a watcher" ok, "what if Spike was a watcher, xander was a wizard and Tara is Buffy's sister instead of Dawn"' too much for me to deal with
I like the characters to basically stay in character. If they get too far away from their basic personalities I usually lose interest.
That being said, there are some all human fics that manage to keep them in character enough that I am transfixed even if the story has nothing to do with canon. The power of good writing!
I like funny short stories. I rarely read porn without plot mostly because it's all the same.
I haven't read any long fics with alternate pairings. Probably because I hang out at Spuffy sites and there is enough good reading there that I don't wander much. I have read short fics of other pairings, some interest me, some not. I'm 2/3 of the way through writing a long fic that ends up Spike/Dawn (buffy was never resurrected) . I might have to write Spike/Ethan just because it sounds like so much devilish fun, and I'm not talking about the sex...my sex scenes tend to be respectfully vague.
One issue I am finding with a lot of WIPs is that they end up wandering too much. Like the writer had a point when they began and then we just end up following the characters nowhere. Even the characters stop growing and it all loses steam. I'd prefer they end it rather than watch it sputter until even the writer doesn't care about it anymore.
My other issue with WIPs is that some writers have too many going at once and there is a ridiculously long time between updates, or they fall in love with one of their other stories and abandon the one they got you hooked on etc. It doesn't feel fair to the readers. I know sometimes real life kicks in and someone has to put a story on hold. But when they have 5 long fics going and are going months between updates then fic #6 starts...I feel cheated.
I'm steering away from a lot of WIPs for completed works because of that.
Most of what I write are long serious fics. What I've posted so far is mostly fluff...which is weird. I have a few interesting concepts I am working on that I will put out into fandom when I get them fleshed out.
I hate abandoned WIPs so much that I won't post any long fics until I have the entire thing at least drafted and through one serious edit. If I am just writing them for myself, then I shouldn't post them if I am writing for others, I shouldn't string them along.