There's a post on the ODD74 forums (I think?) asking if people have distinct associations of setting or fictional source with rule systems. For example, the poster associates Middle Earth (or maybe just the Hobbit) with Holmes Basic. As with most threads on ODD74, the intention is mostly speculative and completely unassuming; there's no implication that anyone's talking about anything other than personal preference or wool-gathering, and the discussion is peaceful.*
* Which is why I'm pretty sure it's on the ODD74 forums. I'd be stunned if there were a peaceful discussion about personal preferences on another forum....
But I am always a little puzzled when people discuss these associations. I obviously don't feel the same way. To me, different rules provide different levels of detail or focus, sometimes unnecessary detail or inappropriate focus, but I actually don't feel like AD&D (1e or 2e) emulate a different world than OD&D or the various forms of Basic. It's just a difference in detail and handling time. I gave up on AD&D because it got too detailed in ways I didn't care for, got bogged down in mechanics, and became too self-absorbed with its own internal details. I like OD&D because it's very minimalist and allows not just differentiation through house rules, but also through "fluff". You can add an assassin class, as Supplement II did, or just run a Fighter/Thief and call him an assassin, or possibly endless other solutions.
My quest for a close clone of the OD&D ruleset is a quest for something that contradicts the original rules as little as possible and doesn't set any expectations of too much detail I don't approve of. It's not because I need that ruleset: I have the original, and I have it internalized, so that I don't even need the books. But when I show potential players a game book, I don't want to have to list too many things I'm changing or deleting, or get into an argument when a player thinks a Light spell should work one way and I'm interpreting it another. But in no way do I think the retroclones, or OD&D, or B/X, or BECM, or even AD&D are representing different, incompatible *worlds*. 3e, maybe, and even more so 4e, because they've done more than just add tons of superfluous detail; but even those fantasy worlds are within spitting distance of stabdard D&D fantasy.
But then, I also think there's a lot less difference between literary fantasy worlds. But that's a different topic entirely.