You might be asking the wrong question. For example, the set of papers satisfying your first question:

What are the most important or personally influential academic papers you've ever read? (call this set A)

has almost no overlap with what I would consider the set of papers satisfying:

Which ones are essential (or just good) for an informed person to have read? (call this set B)

And this is for a couple of reasons. Scientific papers are written to communicate, "We have evidence of a result--here is our evidence, here is our result." with fairly minimal grounding of where that result stands within the broader scientific literature. Yes, there's an introduction section usually filled with a bunch of citations, and yes there's a conclusion section, but papers are (at least in my field) usually directed at people that are already experts in what the paper is being written about (unless that paper is a review article).

And this is okay. Scientific papers are essentially rapid communications. They're a condensed, "I did this!". Sometimes they're particularly well written and land in category A above. But I can't think of a single paper in my A column that I'd want a layman to read. None of them would make any sense to an "informed" layman.

My B column would probably have really good popular books written by experts--something like Quantum Computing Since Democritus, or, like others have said, introductory level textbooks.