I can think of a short list of books that would collectively qualify a reader as serious.
I think serious reading correlates with serious thinking, else there'd be no social outlet for all those curiosities and passions. The OP associates voracious reading with professional writing, where one practice reinforces and drives the other -- a rhythm of life that unsurprisingly seems to thrive mostly among urban writers for periodicals. I've heard that many (most?) novelists are also profound book readers, but often do so from more rural settings. Yet I often wonder where such folks find social sustenance comparable to the urbanite reader/writer. Or maybe they've just learned to live a solitary life of the mind.
The Life of Johnson
Pride and Prejudice
The Waste Land
The Selfish Gene
The Making of the Atomic Bomb
The Modern Library has composed a list of the 100 greatest nonfiction and 100 greatest fiction books.
The NY Times annually posts a list of 100 notable books.
Here's a good "list of lists" for great books:
I've generally used a subtractive approach Bloom's massive "Western Canon" list for generating my own to-read list, cross referencing with other lists to determine what to cut, with supplementation from areas it does not and does not claim to cover (the East, which damn is it a lot of work to find good sources for Eastern works in English translation, science, history, et c.)
Keeping up with the news has about as much value as watching soap operas. Maybe it's fun for you and that's fine, but the notion that it's making one a better person or allowing one to contribute meaningfully to society is mostly BS.
Blah, blah, informed electorate. Meanwhile most people have little or no grasp of the basics of political philosophy and economics, the history of both, are terrible critical readers, know little about the actual structure and functions of their government, and so on, so if your concern is being able to evaluate policy so you can make better choices in the voting booth start with those things. Which... means reading books and journals, not the newspaper or Twitter or whatever.
Wading in day-to-day news is useless or harmful without that foundational knowledge—again, except as shallow entertainment, which if that's what you're into and you enjoy it that's fine but don't subject yourself to it because you think it's making your life or anyone else's better. Even with a good understanding of the relevant topics it's mostly a waste of time unless your job is writing about it (as it is for some of the people in TFA).
This is so true. I am always surprised at how many otherwise intelligent news junkies I encounter who, for example, don't understand the difference between the House and Senate.