As an occasional web programmer I found PHP simple to use and useful. Nowadays it seems to be surpassed by other technologies, but I still think PHP is good enough for many projects, especially thanks to a wide support on servers and the many frameworks that have been created.
For quick documents when I don't feel like using LaTeX, OpenOffice Writer is the choice for me. I've used Impress many times for school presentations. The sheet processor is equally as useful. It's sad people keep using MS Office when this is equally as good, plus free.
For simple programs I keep using ordinary make, it serves the purpose well, use simply type "make" and you're done. The only problem is the required tab characters in the Makefiles - it's inconvenient if your editor is configured to replace tabs with spaces. Also for larger projects that are supposed to be multiplatform I recommend using CMake.
This is the tool for most people when they want to edit or record audio. I am using it and it's great, intuitive, doesn't eat much memory, even has some advanced effects and analysis tools. I once had audacity repeatedly crashing on Windows during recording, but that was a while ago now and I suppose it's been fixed.
This is a great tool to free oneself from Windows. I have personally used it for running a game I was reimplementing so that I didn't have to jump between two PCs. It can save you if someone at work sends you something that can only be read on Windows. It's simply doing the dirty job. Even though we should ultimately aim for native Linux programs, Wine makes it less painful to exist in this world.
This software is so good I don't even know where to begin. It does all I need, without any problems, with a GUI that is among the most ergonomic I've seen. It can map any controller action to any keyboard/mouse action, so you can even browse the Internet with your controller. You can make different profiles for different uses and easily switch between them. My god, thank you for making this.