Harry/Draco. In a way it's an impossible pairing. I don't just mean it's not going to happen in canon -that applies to most pairings. I mean, it's easy to visualise the tension and constant antagonism transfering into sexual release - sex just seems to need the right closet. However, I can't really imagine Harry and Draco in your average fanfic, growing old together, without breaking up due to a) never ending fights or b) losing their spark after even the fights have become old. The pairing seems rooted in the rivalry, the tension and the personal biases that get in the way of the relationship. They wouldn't really be H/D without it but even with it, their relationship probably wouldn't survive.
(Though I have constant faith in Harry beating the odds)
Draco is prickly and high maintanence. Harry ultimately, is his own man - he's used to being the one who calls the shots. They're both characters who practically scream "ME ME ME." And don't even get me started on Severus and Harry - there's something so acidic there that it infuences everything. The revelations of the last book might change that but...if Snape had survived, I still don't think I'd want to read him and Harry slashed 'cause they have too much crazy history between them. So two big slash ships seem kind of difficult to believe. If I had to go for a longterm reationship I'd just find it is much easier to see Severus/Draco with the psuedo-mentor relationship thingy going on.
That's probably why I enjoyed "The Years That Walk Between" by femmequixotic 'cause it showed how much Snaco does make sense while at the same time letting Draco and Harry grow, mature and mellow enough to hook up properly in the future.
If I'm honest with myself, I don't see my OTP hooking up young. They'd break up and get together and break up again and perhaps end up walking away from each other forever because they stepped across the line one too many times.
If they were to love others and grow and have kids and then go through a late 20s/30s/mid-life identity crisis? Yeah, I can see potential long term relationship. Which is why the epilogue to the series might be a blessing in disguise - at least for me personally. I'm a bit tired of seeing teenage H/D when we still have so many possibilities with storyline and relationships as adults. Especially since their relationship might work even better if they didn't hook up from the get go but...came into themselves, as individuals and then got together.
I still recall all my requests last year for fic where Draco would have a kid/heir and Harry would get over Ginny and then they finally get together. And now, as long as the whole of fandom does not go EWE, this might be my golden age for my OTP.
AAAAAAH. Got that out my system. It's so difficult to put all this whole mess of emotions and impressions and preferences into words. Anyone want to share on their OTP? The difficulties, how it does *work*, what you treasure...just spill :)