I quite literally grew up with Harry Potter. I was 10 or 11 when I first read the books and I was a young adult when the last one was released. My super Christian southern Baptist grandmother bought me and all my cousins the books as they released.
Moving from an anime fandom to a book fandom was trippy. Back then slash fans were snobbier than yaoi fans. (I think there's still that feeling that people are looking down on anime/manga fans, but that might be because the stereotype is an overweight male with boundary issues or an obnoxious catgirl with nyan and stuff.)
DracoHarry was my jam. But not the other way around. Despite what slash fans would like to believe, the top/bottom dynamic is also alive and well in slash fandoms as well and has been from the beginning. I prefer Harry as the woobie to Draco.
I found so many different subgenres of fic I liked in HP: Veela fic, mates/creature fic, accidental bonding/marriage fic, arranged marriage, anything with pureblood lore and rituals (that isn't: oh yeah, wizards are 1 generation away from pooping on the floor). I like the Harry gets adopted by [insert character here], the inheritance fics, the x gets turned into a cat, etc.
Harry Potter was good to me, in fact it's only been recently that I stopped dropping into the hp fandom every now and then just to see what's new. I'm still in love with the wizarding world, but I have fell out of love with Harry Potter. Sort of. It's more of as an adult, I hate the way the adults act in HP. Everyone from Dumbledore, to the Dursleys, to Sirius & his parents failed Harry and it pisses me right off.
It's a good story, but it's no longer the world I loved. Thanks JKR.
Onto another book I used to be obsessed about but fell completely out of love with: Eragon. At the time it was published, it was pushed out as a book written by somone close to my age (Paolini is 5 years older than me). I loved any book about dragons, there really aren't enough good books about dragons. It was a decent book, but nothing to write home about.
As an adolscent though, I loved the hell out of it. I called out the twist that Murtagh was Eragon's brother after reading it, much to a friend of mine's surprise when I was right. This was back when I liked puzzling things out instead of deliberately not thinking so I can be pleasantly surprised (but seriously, the foreshadowing was a hammer, not a knife).
It wasn't my first incest pairing, but it was close enough to it. Add in the dragons and well...
It was <3.
Haven't read the third book, probably never will unless I find it somewhere for cheap.
Speaking of dragons and their riders: Pern was a big, big influence on me. I love psychic animals and bonds and especially dragons. I read DragonSinger when I was 10, then DragonDrums because our library was missing the second book of the series. I loved the fire lizards and the background dragons.
Obviously a lot of the stuff (discrimination against green riders and women in general, the rapiness of the mating flights of both dragon and lizard, the backstabbing that went on in Dragonsdawn) went right over my little head, but it had dragons and I loved it. I also liked the whole our technology has devolved thing, that they were descended from colonists who engineered the dragons and the holds. It's fascinating, but again, knowing things about Anne Mccaffrey kind of soured my feelings towards Pern.
(We don't talk about Marion Zimmer Bradley.)