Influences

I've spent hours reading or listening to these people. I consider each of them to be leading experts in their field and great at communicating that expertise. The people on this list have been significant to my personal development and I recommend their work.

Embedded Electronics & Firmware

Phil Koopman
Elecia and Chris White
Phillip Johnston
Jack Ganssle
Michael Barr
John Regehr
Ken Shirriff

Software Development

Joel Spolsky
Jeff Atwood
Scott Hanselmann
Raymond Chen
Michael Lopp

Security & Encryption

Mikko Hyponnen
SwiftOnSecurity
Alan Woodward
Rik Ferguson
Bruce Schneier

Science and Skepticism

Carl Sagan
Isaac Asimov
Steven Novella
James Randi
Jim Al-Khalili
Phil Plait
Ben Goldacre
Simon Singh
Sean Carroll

Philosophy

Daniel Dennett
Massimo Pigliucci
Alex Malpass
Matt Dillahunty
Julian Baggini

Psychology

David McRaney
Oliver Burkeman
Richard Wiseman
Chris French

Worth Following on YouTube

Whilst some of these are not quite as influential on me as those listed above, these channels are recommended:

Electronics

SDG Electronics - Steve Gardner
EEVblog - Dave Jones
Marco Reps
GreatScott!
Kiss Analog - Eddie Aho
w2awe - Alan Wolke at TekTronix
VoltLog
mikeselectricstuff - Mike Harrison at White Wing Logic
Cybergibbons - Andrew Tierney at PenTestPartners
The Signal Path - Shahriar Shahramian
Prof Sam Ben-Yaakov - Professor at Ben Gurion University

Embedded Firmware

Phil Koopman - Associate Professor, Carnegie Mellon University
Quantum Leaps, LLC - Dr. Miro Samek

Software Development Process & Management

Healthy Software Developer - Jayme Edwards
Continuous Delivery - Dave Farley

Podcasts

I listen to many hours of podcasts per week, using Overcast

Current Favourites

I try to keep up to date with:

embedded.fm - Elecia White, Chris White/Logical Elegance
The Skeptics' Guide to the Universe - Dr Steven Novella, Bob Novella, Jay Novella, Cara Santa Maria, Evan Bernstein
The PC Pro Podcast - Tim Danton, Barry Collins, Darien Graham-Smith, Jon Honeyball

Occasional listening:

I've listened to a few episodes of these, some I used to follow avidly. Some are discontinued but still available.

Electronics & Firmware

EEs Talk Tech - Daniel Bogdanoff, Mike Hoffman
EETimes on Air - Aspencore
Embedded Insiders Podcast - Rich Nass, Brandon Lewis, Perry Cohen
The Amp Hour Electronics Podcast - Chris Gammell, David L Jones

Software Development

Complete Developer Podcast - BJ Burns, Will Gant
Crypto-Gram Security Podcast - Bruce Schneier
Cyber Security Sauna - F-Secure
Hanselminutes - Scott Hanselman
The Stack Overflow Podcast
Test & Code: Python Testing - Brian Okken
This Developer's Life - Rob Conery, Scott Hanselman

Science and Skepticism

50 Things That Made the Modern Economy - Tim Harford/BBC
The Digital Human - Aleks Krotoski/BBC
Elements - Justin Rowlatt/BBC
In Our Time - Melvyn Bragg/BBC
The Life Scientific - Jim Al-Khalili/BBC
More Or Less - Tim Harford/BBC
Ri Science Podcast - Royal Institution
Science Weekly - The Guardian
Mindscape - Sean Carroll

Philosophy

Philosophy Bites - David Edmonds, Nigel Warburton
Rationally Speaking - Massimo Pigliucci, Julia Galef

Psychology

You Are Not So Smart - David McRaney

Non Work-Related

All of the above has some influence on my thinking about work-related topics. Those below are purely for pleasure.

Music

Sodajerker on Songwriting
Sound Opinions
The Queen Podcast

Science, Technology and Skepticism

Brain Science with Ginger Campbell, MD
Consequence - JREF
Curiosity Aroused - Rebecca Watson
Digital Bits Skeptic - Andy Kaiser
Hunting Humbug - Theo Clark
Material World - Quentin Cooper/BBC
Point of Inquiry - Chris Mooney
Quackcast - Mark Crislip
Science Talk - Steve Mirsky/Scientific American
Token Skeptic - Kylie Sturgess
Techdirt - Mike Masnick

Software and Computing

Herding Code - Scott Allen, Kevin Dente, Scott Koon, Jon Galloway
Polymorphic Podcast - Craig Shoemaker
The Retrobits Podcast
Software Engineering Radio