Hi all. As you can see, I'm a reader not a writer, so don't have much to say, except that if you're looking for recommendations, feel free to skim through my faves. I mark whatever catches my eye as interesting though, so while they are all awesome in some way, some are fairly experimental, and may not appeal to everyone.
Update: I notice a lot of people mentioning that improper grammar and spelling impacts their ability to enjoy a story. I feel obligated to play devil's advocate and point out that it doesn't impact mine. It's not because I don't know the rules: I received a perfect score on the English portion of the SATs, and proper use of language has been an important part of my job for the last few years. However, I am also multilingual-I am fluent in two languages (which I can also read the ancient forms of), and know enough of a couple more to muddle through newspaper articles and get the gist of what they're saying without a dictionary. That includes a couple Asian languages as well as some European ones, and I've dipped my toes (briefly) in Arabic as well. The result is that I think it's perfectly valid to write left-to-right, right-to-left, or vertically, to put subjects, objects, verbs and adjectives in any order whatsoever, to have three tenses or eight, and so on. 90% of the time I don't even notice what language I'm reading (or talking: I'm serious, people laugh at me for it all the time), so as far as I'm concerned, all the grammar rules (or lack thereof) are valid for all languages. Grammar and spelling rules are pretty darn artificial and arbitrary anyhow, and all too often they neither make any sense whatsoever from a logic standpoint, nor accurately reflect the way a language is spoken by its native speakers in the modern era.
Also, I'd like to point out that there are a huge number of people writing stories in English for whom English is not their native language. I think that's incredibly brave of them, and it's very impressive that many of them write so well that most readers assume the grammar errors are the result of laziness and poor editing.
On a similar note, I also enjoy stories written by people who are not great writers, but are great thinkers--in fact, I love stories that make me think far more than stories that are bland but technically perfect. And I also enjoy stories where author is obviously too young to have the life experience to write a 100% believable story, but the author themselves is a fascinating person, and their unsophisticated writing allows their worldview and thought processes to show clearly. And I've been known to adore stories with beautiful writing but a haphazard, almost incoherent plot. Who cares about plot in the face of beauty? Not me.
Old Update: I find fics to read by looking at the reviews for stories I enjoy, and then looking at the favorites lists of the reviewers who write the best, most thought-provoking reviews. Recently I've been seeing a lot of people asking for stories that aren't ever going to be finished to be taken down. Dear authors, please don't listen to them!! Shall we hide away every Greco-Roman statue missing an arm or head? And what of the sculptor Auguste Rodin, my favorite sculpture ever, whose claim to fame is leaving his works half rough stone, as if he quit working halfway and never got around to finishing? Is the Sagrada Familia Church in Barcelona any less of a masterpiece or tourist draw because it is unfinished? (It has been under construction for well over a century.) I admit, there is even a piece of me that is drawn to unfinished stories, because I can finish them on my own, in my imagination. Not to mention the delightful thought that there's still a chance I might get more of them someday...once an author writes the end, you know there's next to no hope, unless they're the type to do sequels. (And those are almost never as good as the originals anyhow.)
Finished or unfinished, excellent writing is always a work of art, and worthy of preservation. So, I beg of you, dear authors, don't listen to anyone asking to take an unfinished work down. You would rob future readers of hours of fun, and rob yourself of the admiration those readers would give you.
I have so many favorites now...I wish FF.net would put them on multiple pages so it would load faster! But here are a few that are especially spectacular:
http://www.fanfiction.net/s/5398503/1/Embers LOOOOONG Avatar:TLA epic. Intelligent is the best word I can think of for it. It may not match the series perfectly...but I think her version is far more fascinating. All about human nature and political scheming, no romance, with unbelievably awesome character growth (as in, how a normal person can become a better person, not "Yay, I have superpowers".) Mainly Zuko and Iroh, with Toph, a bunch of awesome OCs and the GAang showing up reasonably often also. No pairings
http://www.fanfiction.net/s/5951824/1/The_Fifth_Act FFVII time travel epic. The author's summary is almost as awesome as the story, so I'm just going to use it. "Cloud has an accident with a Time materia. There are people to save, and for that, some people need to die." What the summary doesn't include is the way the author foreshadows EVERYTHING and still manages to have every one of the millions of plot twists surprise the heck out of the reader. Impossible to predict, but oh so very, very well done. A must read. It's THE FFVII epic as far as I'm concerned. The one-shot sequels are pretty awesome too. Yuffie is SUCH a brat... Lots of Genisis & Sephiroth, incidentally. No pairings
http://www.fanfiction.net/s/6556187/1/In_Flight Fate/Stay Night & Sekirei crossover. Never heard of those series? Never fear, neither had I before I read this. And I love it. Near as I can tell, the author took a bloody magic/scifi/war geekfest anime, and crossed it with a boobies and catfight anime. And then took out enough of the boobies and military jargon to turn it into something anyone could fall in love with. Basically, your run of the mill wizard-on-the-lam-from-uber-powerful-secret-organization accidentally hooks up with an alien involved in a fighting competition, and winds up participating. Which ought to be a terrible story, but...it's awesome. Really. Even though it's not finished. He's taking a break for the moment, but he usually updates regularly every week or two. His http://www.fanfiction.net/s/6154638/1/The_Hill_of_Swords is also ridiculously long and a good read, although it's super-powerful protagonist thing is a bit more blatant, so it wears on me a bit. It's ignorable though.
http://www.fanfiction.net/s/7180443/1/My_Mirror_Sword_and_Shield Really, truly awesome Code Geass fic that uses time travel a la Back to the Future to mess with the cannon. Geass doesn't exist, Suzaku is from the future, and...it just WORKS. The time travel takes a dash of suspension of disbelief, but it's so well planned out and written..Everything ties together so perfectly...I spend absurd amounts of time writing sequels to this in my head. Lelouch & Suzaku end up together, but it's not a romance--the romance seems like an aside, to be honest. It's really all about politics an manipulation; morals and practicality and how much value different things (like human lives) have depending on your viewpoint.
http://www.fanfiction.net/s/3764123/1/Mahabharata_Story This is an absolute must read for anyone who likes Asian art but has never been able to memorize all the Hindu stories so you know what you're looking at. Even better, it's a really, really, really good story, with great characterizations, an exotic setting...it's just GOOD. I tried to read the Mahabharata once, and the translation I had was boring. This isn't a translation, it's a story, and it's epic. And incredibly wonderfully written. Seriously, everyone needs to read this.
http://www.fanfiction.net/s/3571049/1/A_Square_Peg_in_a_Round_Hole Medium-length Highlander/SGI crossover. I can not explain the sheer awesomeness of this without spoiling the ending. All I can say is. . . Methos was so totally lying in that episode where he said "History makes men, Macleod, men don't make history." Methos and clone!Jack No pairings.
http://www.fanfiction.net/s/5209349/1/The_Queen_Susan_In_Tashbaan This is midway through an incredible Narnia continuation series, but this is my favorite of the bunch. Basically, Aslan sent them away from Narnia because their home world needed the skills they gained there...and what skills do a bunch of Queens and Kings returned to childhood have that would be useful during WWII? We know they weren't leading nations...this tells what they were doing. Um, do start with the first story. I believe it's http://www.fanfiction.net/s/4985113/1/By_Royal_Decree
http://www.fanfiction.net/s/5344838/1/Atlas I'm sure you've already read this if you like Star Trek. Basically, Kirk is awesome, and the reader somehow doesn't hate him for it because he works so darn hard. My goal in life is to become this Kirk and learn how to give my all, all the time.
http://www.fanfiction.net/s/4110304/1/Cover_Me LOOOONG Transformers fic and one of the very few comedic slice-of-life fics I enjoy. Hurt and with nowhere to go after the movies, Barricade swallows his pride and asks Sam to ask the autobots for help-the autobots say no-Sam hides Barricade-Sam steals repair tools from Ratchet-Barricade makes friends with Sam's Mom.. Darn it, I can't write this summary to sound as absurd and cute and silly as the actual story. Just read it. I die laughing every time there's a new chapter, but it's actually believable. Leans towards slash midway, but it's not a main theme, so it's easy to ignore if you don't like.
http://www.fanfiction.net/s/2422891/1/The_Way_of_the_Apartment_Manager yeah, I'm sure you've already read this too. Medium length, with sequel. Naruto and the friendly apartment manager who takes him under her wing. Awwww...No pairings that I recall
http://www.fanfiction.net/s/3341405/1/The_Broken_Tool Naruto. Medium length, with sequel. How do you make a life for yourself after you lose everything for the second time? A "what if Haku lived" story. Haku x OC, but the OC is well characterized and fades into the background...it's really all about Haku learning who he wants to be.
Secrets by Vorabiza. The only off-site link I've put up here...it's just so darn good I have to send people to it. Harry Potter, Medium length (I guess I should point out that my definition of Medium-length is 100K-250K words). Another "how a normal person can become a better person" tale about growing up, politics, human nature and fighting a war. Slash Harry/Draco, but while the romance is a main theme, the focus is really on the art of influence. What different people value, and how that affects their goals and morality...If I had to summarize it in one phrase, it'd be "how to make friends and influence people" except that for Harry it's more like"What people do when they are desperate and how to help them and save yourself at the same time."