What I Like (Pretty Much In Order):
Harry and...
Hermione, Tonks, Narcissa, Bellatrix, Lily, Luna, Fleur, Hannah Abbott, Fem!Blaise, Lavender, Parvati, Padma, Gabrielle, Susan Bones, Random Beauxbatons Girls (Only if it's a H/Fleur Multi though)
Oh and OFC (Especially dark/independent girls, Kitty from Behind Blue Eyes for instance)

What I Hate:
Ron - I'm not going to get into a big rant about this but pretty much every female in Hogwarts is too good for somebody who will probably become an abusive drunk I'm hoping he'll be the Trio's Wormtail and betray them, and that'll be the catalyst for Harry defeating Voldemort.
Harry/Ginny - I don't hate Ginny, just the way Harry went from not talking to her at all to being in love with her in a week. If it's H/Hr/G or H/Multi I don't mind as much since Pre-HBP she's about as developed as Hannah Abbot, Padma Patil, etc
Hermione The Slut I just don't see Hermione getting gangbanged by Slytherin house.
Nice!Draco - Draco isn't a nice person. I don't care that the actor playing him is good looking, in the book he isn't described that way. He's also a racist piece of trash. If Hermione/Harry were black and Draco called her a ngger would people still be writing H/D and D/Hr fics? If he ended up with Harry, wouldn't Hermione stop talking to him since Draco's been such a racist POS to her for 6 years, and vice versa? If it's D/G how could Harry, Hermione, and Ron stay in contact with such a blatant neo-Nazi(Replace Mudblood with Ngger in the books and then tell me how "nice" he is). Even if Hermione finds out she's a pureblood or Draco decides to not be such a jerk, are they going to forget 6 years of racism towards them?
Pregnancy- I don't care if you're a witch, if you're pregnant when you're 14 you're an idiot
Rape - I worry about the people who get turned on by 13 year old girls getting raped by Death Eaters and still put "fluff" in their summaries. Rape isn't cool and most of the time it's glossed over in 2 paragraphs and the victim forgets all about it and acts normally. This is the quickest way for me to stop reading a fic.

Characters I Hate

Ron/Draco - Discussed above.
Dumbledore - Dumbledore is either the gimmicky manipulative DD from fanon or he's just an idiot who has no idea about people or their emotions. He's the reason Sirius was in Azkaban, and ended up being killed. If he had followed the wishes of Harry's parents (they named HIM Godfather, not Dumbledore or Vernon) Sirius never would've gone after Peter, thus not getting framed, thus not spending his life in Azkaban. Instead of hating Harry for being a wizard, Harry would be far better trained than he is now, and would probably have been taught Occlumency before 5th year, preventing Harry's visions.
Remus - He was supposedly one of L/J's best friends, yet he abandons Harry when L/J probably wanted him to take care of Harry in the event of Sirius being unavailable.Hagrid - Good guy, but too blinded by his loyalty to Dumbledore to do what was right (Giving Harry to Sirius).
HBP!Ginny/HBP!Hermione - I liked Ginny better whenshe was at first the cute little girl with the crush on a celebrity, then later on when she matured and was able to get past the obsession and realized it was unhealthy. Then we get HBP and oh surprise, she's still in love with him and also Hermione is stupid and emotionally unstable and a jerk.

As for Hermione, I hate how she went from Harry's most loyal friend (unlike what took place in the GoF movie, she was with HARRY most of the time, helping him with the first task) to a conniving, jealous, emotionally unstable idiot who is wrong about everything and everyone. Such a sad fate for the strongest female character in the series, who showed that (unlike McGonnagall) you don't have to be cold and repressed to be a smart and powerful female character.

What I Want FF To Add:
- New characters to HP character list (OFC, OMC, Lavender Brown (With HBP she's much bigger than a lot of the characters on the list), Daphne Greengrass, Seperate Fem!Blaise from Male!Blaise)
- Gender selection for characters, so I can browse the fics without having to dig through 500 pages of Harry/Snape fics or any other slash..
- Last Update for Story Favorites, Last Story for Author Favorites
- Default favorites to story favorites instead of that annoying help screen, same with reviews, etc
- Real forums instead of whatever crap we have now, get vbulletin damnit!
- Ability to go to your profile without having to hit "Log In" because it doesn't change when you actually log in.