Here. Have a list. In vague order of fandom, with helpful links!
It was a LONG time ago now, but I can vaguely remember (and probably still have the first draft) starting a script that never was. (I wrote scripts in those days because my brain couldn't accept that a television series would work as a 'book', for some reason - up until very recently it still remained my primary method of scratching out stories because I could focus more on dialogue than action then fill int he gaps later.) It was, of course, a shipperfic, in which Samantha apparently came back and Mulder was literally forced to choose between her and Scully.
Hey, I never said it was an intelligent premise. But at the time, this was the main focus of my fandom-energy, and it was going to be an epic. Unfortunately the plot didn't develop much beyond that initial idea and it fell at the first hurdle...
(I'm not linking to my XF fics because they're horrible. I think they're on my very first site somewhere. I'm not putting a link to that either because it will break your eyes.)
Star Trek: Voyager
I actually finished lots of fics for Voyager (it was one of my most prolific fandoms) because at that point I was still writing the majority of them in script format - however, the last fic I started (and didn't finish) was a four-part songfic series entitled "Bohemian", which was based on the bohemian ideals in Moulin Rouge and focused on the development of the Doc/Seven 'ship. I finished the first part ("Truth" - based on "Elephant Love Medley") and got halfway through the second ("Beauty" - based on "Come What May") and then it froze up. The final two parts were going to be "Freedom" - based on "One Day I'll Fly Away" - and "Love". I don't remember what the last song was going to be, but it wasn't from Moulin Rouge and is probably mentioned in an AIM conversation with doec somewhere...
There was also the provisionally titled "Unimatrix Zero II", another Doc/Seven fic, where they develop a relationship within UMZ, and "Memory" (part of our fictional uber-shippy season eight), which never quite got beyond the initial hilarity, though I did some random angsty pieces to slot in which never made it beyond being one-off scenes.
Though I suppose my 'proper' magnum opus in this fandom was "Minh", which was epically long and kept me sane from my Occupational Therapy placement, but it doesn't count because it's a Mary Sue... :P
Another fairly prolific fandom in terms of writing, especially around season 3, the aptly-named "Season of Death", where I was writing post-episode angstfics pretty much on a weekly basis. My magnum opus here was "Rhapsody" (based on T S Eliot's Rhapsody on a Windy Night) of which I wrote half as a first chapter and then lost the imagery completely. It does remain one of my favourites, though.
There were also about six million crossovers that never got off the ground: Leviathan Rouge ('Scape/Moulin Rouge), 'Scape/Les Mis, 'Scape/Phantom, The Wizard of the UT (it even had pictures!). The only one that ever saw the light of day was "The Farscape Horror Show", which never got finished...
Tango Up On Sunset" has been one long ongoing story since the moment I started - it had a plot outline and random scenes written all out of order - it even had some 'director's cut' missing scenes. ;) Yet, despite the manic period I spent writing endless reams (I'm not even kidding - I'll photograph the pile later) of SB-fic, the main fic never quite got finished. Seven chapters out of about 20, plus extras. Ah well. It's ironic especially because I intended to finish it before we saw the show in September 2002 (or was it 2001?) so I could hand Faith Brown this massive leather-bound tome. ;)
Phantom of the Opera
I'm putting POTO here because it's been an ongoing fandom throughout the others, but the opus fell around about this point. And it was - or is, I should say - "Sweet Intoxication". This fell apart around about the same time I did, and the most annoying thing is it was so very nearly finished... I think there's only about three chapters to go.
I will be posting a new POTO fic soon, but it's taking a while to get ready... Hopefully any reviews for that will poke me back into writing the other one.
I'm putting this one here also because it's been an ongoing fandom. I've written a few short fics for this, but the longer ones never get completed properly. My latest one (the drabble continuation which still needs a name) is going to be my magnum opus in this fandom, more than likely. The only stumbling block I have with JC, as discussed recently with Eni, is that Jonathan/Maddy fluff is immensely satisfying, but impossible to pitch right because of the sheer amount of snark. Getting it right is difficult, and I've written and re-written at least three separate J/M final shippy scenes and still failed to get it quite right. I suppose it's a learning curve; my desire for proper characterisation and canon makes it all the harder, though.
Buffy the Vampire Slayer
Another fairly prolific fandom - that was my favourite summer, I think. I have two for this one, technically. The first is "Cradle", my post-season-6 epic, but I don't really like to count that one. It was my very first BTVS fanfic, and even though it remains one of my all-time favourites of my own fic, I can now admit that it has plenty of flaws. That being said, chapters 17-20 are my absolute favourite part, and there are some moments in it that I remember being total "AH-HA!" moments when I thought of them.
The proper one is "Broken Record", my post-season-7 maddeningly-clichéd epic songfic. This was the very pinnacle of my writing - along with the two stories it followed, Counterpoint fics for "Touched" and "Chosen" - and I only got three chapters into it (the listing says five because of the prologue and the fact that Chapter Two was broken into two parts...) Another one that fell apart at the same time as my brain. I really do want to try and finish this, and if I ever get around to re-watching the series I'm hoping it'll reinspire me. I put too much effort into picking songs, making notes and getting the feel of the final scene perfect to not finish it now, dammit. The thing with "Broken Record" is it's not final - there was going to be a sequel, too. It was meant to be an exploration of Buffy becoming normal again (excuse the pun), growing up, everyone becoming adults, the potentials become Slayers, but everything coming full circle again to a great battle. And it was glorious. I read it today and yearn to be that good again - I'm not blowing my own horn, here, not really - it's just the level to which I aspire now that my Muses have awoken. Mostly I regret that I lost it.
I should mention the Crossover of Doom here, if only because that was also going to be epically long and take in more fandoms than you could shake a stick at: initially Buffy and Farscape, then spreading to Harry Potter, Discworld, Priscilla, Voyager, Angel, Pirates of the Caribbean... I fear if Naomi and I had ever gotten further than the first chapter (and that random scene in the Bronze), it would have eaten our brains. Ah, well. I relish the memory of what it almost was, nonetheless. :)
My last fandom before Ugly Betty, and even though it's technically not a fanfic, "Come Forward" was a really plausible attempt a novel, until the series started being poo. It was unfortunate that MH stopped being enjoyable around the same time as I lost the ability to find enjoyment in anything, really. I want to finish this, too - I got quite attached to Yvelyn, Alec and Mark, and there is an entire chapter outline on my PC...
My actual proper might-do-something-with-this-one-day thing is "Reclamation", née "Orphan Eyes", the movie script-slash-book which is still lying dormant in my brain waiting for release. One day, my pretty. One day...
I don't have one for Ugly Betty yet because I've only just started. I'll keep you posted, though "Strange Glue" is shaping up to be similar in form, as it explores emotional and character issues and very little else.
We have a 'new' PC from a bloke at Paul's work. Unfortunately it's a desktop (not a tower) but hopefully should work better than the one we have at present. I might ring my mum this afternoon and see if she still has her external Zip drive (mine is internal) and failing that, find a nice person to swap it for me. ;) Otherwise I'm going to have to put everything onto CD - along with everything on the old HDD.
I'll hopefully get around to plugging it in tomorrow and have a proper look at the spec then. In any case, it's free, and it can't exactly be any WORSE. :P
I'm going to lunch now. Over and out.
Edit, 18.21: I added another fic to the list. Have PC; must now do copious copying of things to CD.