To this list I’d add Daniel Dennett, my favorite contemporary philosopher, and George Gamow, writer of the beloved “1,2,3 Infinity.”
I know he’s dead, and that the OP seems to be looking for people who are still around, but i think that Richard Feynman’s Caltech lectures are still classics of clear explanation.
I love Six Easy Pieces: Essentials of Physics Explained by its Most Brilliant Teacher, which contains 6 CDs of Feynman’s introductory lectures, as well as a book that follows along with the lectures.
Once you’ve grasped that, you can move on the Six Not-So-Easy Pieces.
He’s a fabulous lecturer, and very amusing.
And I think Steven Pinker might be one of those. I’m surprised he’s not mentioned more here though. I know he’s stirred up some hornets more-so with The Blank Slate as opposed to his work in linguistics.
Richard Rhodes
Rudy Rucker did a few good math books.
How about Larry Gonick?
*ref the link and the startup year for Larry, coincidence? 
He was my professor in college, another one of his books, The Pencil, does pretty well on design and the evolution of technology.
Ifs its sci and maths broadly, and up-to-datedness that you are looking for, why not subscribe to ‘nature’ or ‘science’? They write for the educated lay.
or new scientist if you wanna dumb it down a bit
Someone already mentioned Simon Singhe for Fermat’s Enigma but Singhe also wrote “The Code Book,” which is in my top 5 non-fiction books to date. Fascinating chronicle of cryptography through the ages.
Of the ones I have read, I agree with most of the recommendations.
I add Timothy Ferris - who’s Coming of Age in the Milky Way and The Big Bang are great.
I also second the nomination of Larry Gonick - his Cartoon Histories are great. I am reading the Cartoon History of the Universe right now for my son, and it is accessible while still written at an adult level.
For good books that are accesible without a heavy math and science background, Michio Kaku, John Gribbin, and Paul Davies are all excellent science writers with a number of books. Two of Kaku’s best are Hyperspace and Visions. Gribbin and Davies have a huge number of books between them, all good and accesible without heavy math or science backrounds. For math, people have already mentioned John Allen Paulos, who has written several good books including Innumeracy and A Mathematician Reads the Newspaper. Jonathan Weiner writes very good science books, over a range of topics. Time, Love and Memory is a particularly good one by him.
Electronics/computers and such - I would go with Scott McCartney’s ENIAC. It’s actually exciting!
Bill Bryson’s A SHORT HISTORY OF NEARLY EVERYTHNG knocked me out. It’s written for lay people, by a layman who bothered to learn some of the rudiments of what used to be called natural science. Witty, clear, thoughtful.
For kids - *The Number Devil * by Hans Magnus Enzensberger and The Parrot’s Theorum by Denis Geudj - both make maths an adventure
Jay Ingram is a great pop science journalist. He has written several books and newspaper articles. I used to love “Quirks and Quarks”, his radio show on the CBC.