Here is a growing list of who I've read or listened to, and highly recommend. Since I read both fiction and nonfiction, I'll have a mixture of both listed here:
Seth Godin - marketing genius.
Dan Miller - career coach and entrepreneur.
Dave Ramsey - financial guru and entrepreneur.
Simon Sinek - inspirational author.
Writing Excuses - amazing weekly podcast by four accomplished fiction writers: Brandon Sanderson, Howard Tayler, Dan Wells, and Mary Robinette Kowal. Their tagline is: "Fifteen minutes long, because you're in a hurry and we're not that smart." The last part, of course, is a lie--they're brilliant. Ranked as one of the top podcasts in the fiction writing arena.
Guide to Literary Agents - blog maintained by Chuck Sambuchino, the editor of the Writer's Digest Guide to Literary Agents. Chuck blogs practically daily, and the site is full of useful info for the fiction writers out there.
TED Talks - this site is a wealth of knowledge, with videos of varying length on a variety of topics. Minimum length is 3 minutes, and the average is 18.
I Should Be Writing - blog and podcast hosted by Mur Lafferty, fiction writer. Ranked as one of the top podcasts geared towards creative writing.
Reading and Writing Podcast - podcast hosted by Jeff Rutherford. Jeff interviews several fiction writers about their path to publication, their writing style, and much more.
The Tolkien Professor - podcast hosted by Professor Corey Olsen, who lectures on everything Tolkien, from The Hobbit to The Silmarillian and even on medieval literature in general. A must-listen to for all Tolkien lovers.
This Is Your Life by Michael Hyatt - former CEO of Thomas Nelson Publishing. This weekly podcast is a must on improving the quality of your life, your leadership, and your daily productivity.
The Dead Robots' Society podcast - weekly podcast for aspiring writers, by aspiring writers Justin Macumber, Terry Mixon, and Paul E. Cooley
ThrillerCast podcast - podcast hosted by Alan Baxter and David Wood, for both readers and writers of the thriller genre.
Speculate! - podcast hosted by Greg Wilson and Bradley Beaulieu regarding the fantasy/science fiction publishing industry. They even do something unique and that is dissect various genre books down into what works and what doesn't.
Adventures in Sci-Fi Publishing - bringing to listeners authors of science fiction and fantasy.
SF Signal - Hugo Award winning podcast, hosted by Patrick Hester, on the world of science fiction and fantasy.
Fictional Frontiers - podcast hosted by Sohaib Awan, on the SF/F world, including the Star Wars Expanded Universe.
The Roundtable Podcast - podcast hosted by literary alchemists Dave Robison and Brion Humphrey.