Well, this one is tough for me to answer. I don't really run adventures. Ever. Sometimes I read them. But not to run them, only to raid them for ideas. So I literally have no idea what to answer for this one that really is completely "on topic."
So instead, I'll "cheat" just a bit. While I've never run any D&D adventures that I can think of, I have run the infamous DARK•MATTER adventure, "Exit 23" (which was included in the original campaign setting book) several times. Although never in its original Alternity form; I've run it adapted (by me) to d20 Modern. This little gem of an adventure is about perfect for a 4 or so hour convention game, which is about how I've always done it, although I added a little more to make sure it filled the time completely. It was meant, I think, to be done with six players (and that's mostly how I've done it) but I've done it before with an impromptu seven too.
It also helps that as a convention game, you can really play up the horror angle a bit more. If a character goes down, well, that's OK. It's just a couple hours of one-shot anyway. The horror angle is handled very well; there's really only one monstrous encounter (an ice demon of some kind) but this is a great example of how to "milk" a monstrous encounter so it doesn't feel routine (as is so often the case in D&D.)
I honestly can't even remember ever running another another pre-written adventure--of any system--other than "Exit 23". So, while it's not a D&D adventure, I think it probably has to qualify.
That said, I'm a little tempted to adapt some Paizo adventure paths into something I run for my group. They'd be heavily adapted, but they'd still be more or less recognizable. I think either Carrion Crown or Serpent's Skull are the ones that most catch my eye.