XOJO– Object-oriented integrated development environment that lets you do drag-and-drop development of GUI-based applications that will run on Windows, Linux and Mac without having to rewrite much (if any code). Also a much simpler API model than .NET for those of us who don't want to spend a lot of time becoming code gurus. A unique feature of XOJO is that the GUI organizes code using a hierarchical listbox down to the object, control and method, and variable level. This took me a little getting used to vs. a text-file based approach, but after a while I found I actually preferred it as it made organizing my code easier. While XOJO isn't open source, the pricing structure is pretty reasonable, and you can use the 'free' version to edit, debug and run programs - you only need to buy a license when you want to generate EXEs.
The Economist - My favorite source of news. You can either get it digitally or in the form of dead trees delivered to your mailbox weekly. While the magazine does have a somewhat conservative bias, they make a real effort at reporting important news and developments from around the world, and providing thoughtful analysis. Not cheap, but definitely worth the money.
OCTAVE - An open source mathematical programming language very similar to the commercial MATLAB system. Runs on both Linux and Microsoft Windows. Recent revs include a built-in GUI that vastly improves usability over the command-line version.
R and RStudio - Open-source statistical computation language and a supporting integrated devleopment environment that makes it user friendlier. Because R also includes a general-purpose programming language, it has vastly more flexibility than the typical 'canned' statsistics package. And because it has more than 5000 add-on packages available, R can handle nearly any statistics problem you can imagine, and lots that you can't.
FEMM - A 'free' 2-D finite element simulation package for electromagnetics and thermal problems. Provides a graphics user interface with geometry editor and extensive output plotting options. I have been using this package for years for the day job and have found it it to be incredibly useful.
Hall-Effect Sensors: Theory & Application -2nd edition - Another shameless plug for my book on Hall-effect sensors. Also available at Amazon and Barnes & Noble.