The following rankings are the products of logic and maths and cannot be reasonably disputed.
1. AD&D (1e).
Why it's great: Any list of the greatest modules/adventures/whatevers will heavily feature these adventures, and for a reason. In fact, these adventures are so well-known and well-loved that they continued to be reprinted and updated throughout the editions, including 5e.
I'll like to discuss this point!
IMO, many AD&D 1e adventures are so well appreciated because they are the first examples or exemplars, so they became classics, and not always because they are at the top.
Yeah, for example, I played Against the Giants and it's great, but the plot is really "enter the dungeon and slaughter everything". Over and over and over. The same with Keep on the Borderlands.
Let's take White Plume Mountain. It's fun, but in the end it's an illogical dungeon, full of overpowered weapons that WILL destroy your campaign. The same could be said of the ultimate funhouse that is Castle Amber.
I dare to say that the early modules, even Gygax', were lacking story. You had to clean a dungeon, and more often then not it was a fun but incoherent mess.
After the "Hickman Revolution" with Dragonlance and Ravenloft, the story became predominant. And that had two limits: first of all, the adventures became railroaded. Second, especially in the good old days of 2e, the story was so important that the crunch was sacrificed. The encounters were not always well balanced, and in fact before the introduction of Challenge Rating it was a mess!
3e was the time of rationalization even for adventures, and in the Dungeon Magazine they achieved a good balance between story (again, railroady) and crunch. But high-level play became very complex because of the numbers.
(I skipped 4e...)
IMO, 5e is trying to produce adventures that are an alternative to Paizo's railroads. Each 5e Adventure is a mini-setting, so that it HAS a definite story, but at the same time it's NOT a railroady because It can be played in a number of different ways. And it is successful!
I am very very happy with the adventure design of 5e, in this sense they are the best because they combine a story without being railroady, and that was difficultà to achieve.