Below, I've given a selection of some of my favourite articles by various authors.
Edge 2011 Annual Question: 159 famous scientists and thinkers describe their idea of the important scientific concept that improves how we think about things. This might actually be the most useful webpage published on the internet.
Why Most Published Research Findings Are False: to get an idea of the scary awesomeness of this article, skip straight to the corollaries and the comments about 'null fields'. Also, hurray for open access!
General Systems Theory: The skeleton of science (1956): A really enjoyable paper that talks about the way science and research is conducted, in particular interdisciplinary and multi-disciplinary science. The comments on 'fragmentation of disciplines' and increasing inability to communicate between research niches seem insightful for their time.
Cargo Cult Science: An essay by Richard Feynman covering pseudoscience, scientific honesty, sharing data, repeating experiments, and how we can fool ourselves.
Life & Work
You and Your Research: This is a transcript of an amazing talk in 1986 by Richard Hamming, on the issue of 'What should you be researching - and why aren't you researching it?". It completely changed the way I think about my research.
Steve Jobs commencement speech at Stanford University, 2005: Extremely inspiring - why aren't you doing what you love? - try to do amazing things and don't let other people's opinions stop you. Particularly interesting given the challenges he has overcome during his life. It also underlines the importance of serendipity in shaping your life.
Against productivity systems: This article talks about maximising productivity vs. fun, creativity and finding important work that you love.
Goodhart's Law. Modern academia is plagued by metrics and targets. This article talks about why target-setting based around single metrics is generally not a good idea.
The Superinvestors of Graham and Doddsville: If the richest guy in the world wrote an academic paper explaining why he became rich, and providing data to show that it was a result of specific techniques rather than luck or personality, you would think academics would be queueing up to read what he had to say and imitate it. Yet most people have never heard of this interesting and amusing academic paper by Warren Buffett. It absolutely undermined the central tenet of academic finance and economics at the time it was published (efficient market theory)... yet the majority of academics in finance/economics completely ignored it at the time and have continued to ignore it for more than 25 years. Apparently being right in practice isn't as important as being right in theory...!
Technology & Progress
Innovation Starvation: This article by Neal Stephenson talks about the lack of vision in our current generation, and our increasingly inability to get big projects done and big problems solved. He presents some interesting ideas about the use of logically consistent science fiction story worlds as a way to coordinate the long-term vision of scientists and engineers. He encourages the use of strategic ignorance as a way of preventing good ideas from dying on the drawing board.
Unicode and character sets - the bare minimum a programmer needs to know: Many programmers don't bother to make their software / programming languages compatible with unicode rather than ASCII, so that they can correctly handle text in Russian, Chinese, Japanese and so on. The good news is that it's not really that difficult to learn.