Greetings fellow fans of fanfiction! I am a Harry Potter fan, and an addict of Harry Potter fanfiction. My favorite pairing is Harry/Ginny. While I enjoy Ron/Hermione as part of a Harry/Ginny story, I don't go out of my way to read that ship. Other pairings I like to read are Hermione with Bill, Charlie, Draco, Fred, George, Lucius, Remus, Severus or Sirius.
As you can see from my favorite stories (which doesn't include all of them yet), I like the soul bond story ideas. It is a hard form to write in, as it is easy to cross the line into Super Harry. I like soul bond stories that bring Ginny and Harry together earlier than JKR did, yet still lets them be kids.
The marriage law fics are also fun to read. Of those, my favorite pairing is Hermione with either Draco or Severus. While they are obviously not supported by cannon, I like reading Hermione taking on either of those two, strongly opinionated and stubbornly pigheaded characters.
Veela mate stories are also good. Some, however, lead the reader through such high angst, bring the characters together finally, then write as if the characters were always in love.
Slash stories are always ignored. It is just too hard to pull these characters that far out of cannon, and still enjoy the read.
I have been reading fanfiction now since Half Blood Prince was released. I have found many sites that have great fanfiction, and others that don't. Some sites update quickly (this site is one) while others show a story as updated but don't authorize people to read it of over a week. I am happy to have found this site, to read and share in others' opinions on the Harry Potter verse. There are MANY, MANY awesome stories on this site, that have brought out points that I feel would have added greatly to JKR's vision for Harry. But, it is still just entertainment, as the true Harry Potter universe was established by JK Rowling.