Links

Here are some links you might find useful:

Generalist websites

/r/photography on reddit – this is where it all started, and a great community for general photography discussion. Just make sure to read the sidebar before posting!
dpreview – very gear oriented, home of technical reviews and very opiniated reviews.
fstoppers and petapixel – aggregator blogs, lots of (second hand) content, can be clickbaity.

1x.com – a somewhat elitist website with very strong curated content.
The Online Photographer – in a world full of self-promoting photo blogs, TOP is a breath of fresh air, offering wonderfully insightful writing and not delving too heavily into gear masturbation.

Strobist – the absolute best place to learn about lighting. Very accessible blog and lessons (dig in the archives) from David Hobby.
Thom Hogan – Thom has been writing about cameras, the industry and photography in general for ages, and his insight is always very valuable.
Creative Live – lots of video classes on both technical and business content. Free when they are running live, then accessible for a fee.
Lynda and KelbyOne – both are subscription websites offering video courses on a variety of subjects, many related to photography.

Ansel Adams, The Camera, The Negative and The Print – written in the era of film and darkroom printing, its principles are still very valid today.
Bryan Peterson, Understanding Exposure – the reference textbook on exposure, and hence on photography in general.
Fil Hunter, Paul Fuqua, Steven Biver, Light, Science and Magic – dry in places but extremely thorough, this is the reference for all forms of lighting.
David duChemin, Within the Frame (and all his other books, really) – a great book on composition from somebody who really took the time to stop and think about his art and his craft.
Joe McNally, The Moment it Clicks – tales from one of the greatest shooters of our time. Very easy to read, and one learns surprisingly much from it as well.
Dan Winters, Road to Seeing – a very unique and beautiful book, on the surface an autobiography of one of the top commercial photographers but really so much more…
Greg Heisler, 50 portraits – if you are interested in portraits at all, this will be invaluable learning from the greatest.