I recently finished http://startupclass.samaltman.com
Could be a book, course, podcast, blog post - anything - as long as it's something you can link to. Hopefully we can all benefit together
This is going to sound cliched, but the best way is to start your own company or project from scratch and apply the concepts you learn from these resources.
Here are some "bestsellers", apart from http://startupclass.samaltman.com and PG's essays are
Building Product/Design
-----------------
* Design Sprints by Google Ventures: https://www.youtube.com/results?search_query=design+sprints
* Startup School Office Hours: https://www.youtube.com/results?search_query=startup+school+...
* Interface Design for Startups https://courses.platzi.com/classes/interface-design-startups...
* The Design of Everyday Things: http://www.amazon.com/Design-Everyday-Things-Donald-Norman/d...
* Don't make me Think: http://www.amazon.in/Dont-Make-Me-Think-Usability/dp/0321344...
* Objectified: http://www.imdb.com/title/tt1241325/
* Either Rework or Getting Real by 37 Signals
Execution/Business Models:
---------------------------
1. The Lean Startup: http://theleanstartup.com/book
2. Lean Analytics: http://leananalyticsbook.com/
3. Business Model Generation: http://www.businessmodelgeneration.com/
People:
-----------
* How to Win Friends and Influence People
* The Hard Thing about Hard Things: http://www.amazon.com/The-Hard-Thing-About-Things/dp/0062273...
* The Startup of You: http://www.thestartupofyou.com/
Marketing:
----------
* Build an audience before you launch the product - like 37Signals, Jeff Atwood and Joel Spolsky, Hubspot
* Traction Book: http://tractionbook.com/
* Be Creative - Each startup is different. There's no silver bullet
Sales:
------
The sales course by Steli Efti: http://close.io/free-sales-course/
Pitching:
-------
Dave McClure: https://www.youtube.com/results?search_query=dave+mcclure+st...
Founder Interviews, stories:
----------
* PandoMonthly: https://www.youtube.com/results?search_query=pandomonthly
* Stanford ECorner: ecorner.stanford.edu