"The DADA Professor" by RJLupinFan

I don't really know what to say about this fic.

http://www.fanfiction.net/s/4088288/1/The_DADA_Professor

It's about a seventh year student who gets a crush on Lupin while he's teaching at Hogwarts. It's bit hackneyed in some respects, and the writing's rough, but it's charming. It's not about a Mary Sue gushing about a Professor, it's as canon as one of these fics can be, minus one eye-rolling, backbended way of getting Lupin and the student to kiss.

I don't know. There's something to this fic. It's worth reading.

"A Cure For Nightmares" by picascribit

This fic is so sweet it gave me toothaches.

http://www.fanfiction.net/s/6361279/1/A_Cure_For_Nightmares

This is really just your run-of-the-mill RLSB Marauders era fic, with minor twists, but this fic is so straightforward, that I kind of respect it for that. It doesn't pretend to be anything other than what it is.

Edit: I've decided to clarify, for the sake of my reader, that this fic does deal with some touchy subject matters, and that some people find those kinds of subject matters pointless in fanfic. I typically very much agree with that assessment. However, because this fic is obviously trying to channel canon, I accept it in this case, and I don't think it's exploitative or in bad taste, but some may disagree. 

The "Alexandra Quick Series" by Inverarity

A series about an American witch at an American wizarding institution.

http://www.fanfiction.net/s/3964606/1/Alexandra_Quick_and_the_Thorn_Circle

http://www.fanfiction.net/s/4684861/1/Alexandra_Quick_and_the_Lands_Below

http://www.fanfiction.net/s/5784632/1/Alexandra_Quick_and_the_Deathly_Regiment

One of the few things Rowling got right in the last books was that she didn't address the Veil, (and I commend her for that because in every other regard she threw subtlety out the window,) but Inverarity discusses the Veil head-on, and comes out with a pretty good story.

I love this series. It's especially amusing if you know anything at all about American history.

I believe it's Inverarity's plan to write seven books (admirable, really), and the series is much more tightly-connected than the HP books, I would say. Book three feels like the second half of book two, for example.If I had to make any complaints, it would be that I miss some of the canon characters we know and love. There are references to canon sprinkled throughout, but it's not quite the same, you know?

And also, I'm just stating for the record that any coincidences between this series and the (non-fan)fiction series I'm working on are purely that. We even use similar names. Maybe that's why I like this series so much. Sheer narcissism.

"Wanderings with Werewolves" by ishandtwofourths, and "Caring For Magical Creatures" by MrsTater

These are... sister fics, if you will. They look a lot alike, but one looks a bit more like their grandmother, while the other clearly favors their dear Aunt Prudence.

http://www.fanfiction.net/s/4458074/1/Wanderings_with_werewolves

http://www.fanfiction.net/s/3448191/1/

Lupin/Tonks meet during Lupin's run at Defense professor. Tonks is trying to solve a case, and Lupin is helping. I actually prefer "Wandering with Werewolves," but MrsTater is clearly the superior writer. I don't know. They're Charlotte and Emily Bronte.

Writing Suggestions from Yours Truly, Number Three

Don't put author's notes every chapter. Don't over-rely on footnotes. Don't ask for reviews. Don't use smileys. It's unnecessary. Just post the goddamn story.

"My Immortal" by XXXbloodyrists666XXX

I don't really need to talk about this story, I just wanted to post it because I genuinely love it. If I had to name my favorite fanfic, this would probably be it.

http://myimmortalrehost.webs.com/chapters122.htm 

"The Misadventures of Draco Malfoy, Ferret" by Saber ShadowKitten

Just ... read it.

http://www.fanfiction.net/s/2690275/1/The_Misadventures_of_Draco_Malfoy_Ferret

Writing Suggestions from Yours Truly, Number Two

The Sirius/serious pun is majorly stale.

... But I still laugh at it. Every time.

"Marauder Reminders" by Jenulus

This is an unfinished Lupin/Tonks fic that, to me, portrays their relationship in the most canon-honest way.

http://www.fanfiction.net/s/2257981/1/Marauder_Reminders#

I think it was Jenulus's original intention to cover their whole courtship, but she only managed to get nine chapters in, so she covers their first meeting at Grimmauld Place and their growing friendship/flirtation.

I just really like the way she portrays these characters. Tonks, in particular, is wonderful, as she is a bit gruffer in this fic than most others.

I'm breaking another one of my rules by posting a piece that's unfinished, but who cares. This had a really, really good start, and it's worth looking into.

"The Gospel According to Lupin" by Scandalacious Intentions

This fic has just finished, and it's very cute.

http://www.fanfiction.net/s/5709995/1/The_Gospel_According_to_Lupin

It's a series of notes Lupin left to Teddy.

"'The Parallel Worlds' Series" by LouisaB

When I started this blog, I decided to only recommend one fic per author, and that was it. After just a couple of months, I'm already bending the rules, though in my defense, it's for an interconnected series.

http://www.fanfiction.net/s/3920327/1/Double_Trouble_COMPLETE


http://www.fanfiction.net/s/3959071/1/Triple_Trouble_COMPLETE


http://www.fanfiction.net/s/4072843/1/Trouble_with_a_Capital_T_COMPLETE

I left out one story there - "Catch a Quaffle," technically second in the series, though it has nothing to do with inter-dimensional Marauders as it does Remus/Sirius fluff. And I just don't care about that.

After accidentally opening a portal and finding a parallel universe, the marauders (and Lily!) get into all sorts of adventures and wacky hi-jinks. These fics are actually really well-written, enjoyable, and pretty damn brilliant. The different marauders running around at all times is sure to make you smile. I doubt these fics would be half as popular as they are if it weren't for the RLSB aspect, but I actually feel like that's the weakest part to the whole series.

"Harry Potter and the Slytherin Spy" by Christine Morgan

What if there was another Hogwarts student in Little Whinging?

This fic, written/set right after Order of the Phoenix, is about Harry meeting a Slytherin girl and forming a friendship with her in his sixth year. It's fairly-straightforward and not excessively (wonderfully) violent at all. (Sarcasm.)

http://www.eskimo.com/~vecna/hp_spy_01.html

Morgan can imitate Rowling's writing style well, and there is something so satisfying about reading a fic you can confuse for the genuine article; especially when it gets to where Morgan is describing gruesome deaths in Rowling's simple, yet descriptive prose.

I'm not pretending this fic is without problems; it's focused on a female OC, which is a no-no to most in the fandom, though trust me when I say the writing is good enough you won't care. And there are a few canon things that would raise eyebrows - Kreacher's characterisation is all wrong in this fic, in my opinion, while I think Morgan's explanation of where Sirius was hiding during Harry's thirteenth summer is a brilliant twist. Morgan also abuses ellipses, and the ending seems a bit rushed and simplistic, but trust me when I say:
YOU SHOULD READ THIS.

"Rise from the Ashes" by MidniteMarauder

Out of all the stories I thought I'd rec here, I never thought one would be a Teddy/Cedric fic, but here we are.

http://www.fanfiction.net/s/3991733/1/Rise_From_the_Ashes

I can't think of how to describe this fic without giving away the plot. It is a Time Travel fic, so that should tell you all you need to know. It's only eight chapters, and they're pretty short, so the story feels a bit rushed in some ways - for example, certain people seem to accept Teddy's identity a bit too easily - but, for the most part, this fic has a great story and is an enjoyable read.

Don't worry about the pairing, either, because the slash isn't dominate and is handled really well.

Writing Suggestions from Yours Truly, Number 1

Never end a chapter with someone fainting.

It's hackneyed.

"Alexandrite" by Pandora Culpa

Pandora Culpa wrote the book on the Lupin/Tonks pairing. You should check it out sometime.

http://www.fanfiction.net/s/2225991/1/Alexandrite

"Loved By All" by Draug419

Wow. This is a weird, weird fanfic. And I mean that in a good way.

http://www.fanfiction.net/s/5092272/1/Loved_By_All

I can't even really properly tell you the plot without giving anything away. It's Remus/Sirius, but, once again, that is more of a backdrop to a really, really weird story. It's an AU, and Remus, Sirius and James (there's never any Peter in these things, is there?) attend another wizarding school, which is Hogwarts minus the charm and warmth. What you have here is a thriller that I couldn't stop reading almost despite myself. I kept wondering, What the FUCK is going to happen next?

Draug's writing isn't particularly good, but she does have a knack for interesting plots (she could almost release this as a whole new novel, given the way it strays from canon; I think she was influenced by The Chocolate War, but let me just say, it's not very much like that book, either), and she introduces some interesting concepts about magic (Imperius vs. Veritaserum for example) and that's where the rec comes from. A place of WTF.

"The Spy Game" by ttfn.tahtahfornow

This is a really lovely AU fanfic; it's subtle Remus/Sirius, but there's so much more to it than that. It's basically written as if the Marauders were muggles and neighbors and went to the same school.

http://www.fanfiction.net/s/3622968/1/The_Spy_Game

The plot to this fic isn't exactly amazing, but ttfn's writing style is really lovely. It's more a collection of viginettes than a fleshed out novel, but the pacing is done well - so well, in fact, that her lack of description seems to be almost the perfect way to write. She never hits you over the head with anything, and when the threads come together, you just have a nice a-ha moment in your head.

If I had any complaints it would be that it's a bit angsty, but not even I, who HATES angst (I really do), was turned off by this fic - the author just hands it all so delicately that scenarios that would be eye-rolling in any other fic just make you desperate for more in this one.

"The Dating Disasters of Sirius Black" by KaleyK

I was, for the longest time, anti-slash. It was in part because everyone and their dog were writing Remus/Sirius stuff and frankly, I never liked being part of the crowd, and also because it just didn't appeal to me. The chemistry between the pair had never seemed right. I was a big fan of Lupin/Tonks, though, and I was taunted quite a bit about that by "puppshippers" (this was before HBP came out and proved me right, of course).

That said, I loved reading Marauder-era fanfic and, basically, a lot of it was slash. This was the first Remus/Sirius fic that really clicked with me, though. It was the first time I thought, Well, all right, I can buy that, I suppose.

http://www.fictionalley.org/authors/kabeyk/TDDOSB.html

This fic has a great build-up, great character-development all around, nice writing in general. None of it happens too fast, and the Shakespeare parallels endlessly amuse me. This is the example of more-than-bearable slash, and, more than that, it's the example of why stubborn assholes (myself included at one point, I'll admit) shouldn't overlook the genre.

"Empty Classrooms" by Bowles

My first recommendation is going to be a fic that I first discovered just a month or so ago, and I have been unable to stop thinking about. It is about Hermione inheriting an academic tract that Lupin had been working on almost his entire life. In it, he begs the question: Why does Hogwarts have so many empty classrooms?

http://www.fanfiction.net/s/5423450/1/Empty_Classrooms

I am recommending this fic because it is very, very brilliant, it is about a concept that, as far as I know, has not been delved into before (and is so wonderfully worth considering that it's almost as if every question I have ever had about the HP universes has been answered), and just, in general, is exactly what I think Harry Potter fanfiction should be. Great, great stuff. Can't recommend it enough. The descriptions about the dark magic get a bit repetative toward the end, but it's worth looking in to at any rate - especially if you're tired of dramatic, slash-y stories written by 14-year-olds (not that there's anything wrong with those)!