"Technology Nigh Perfection"
Gimp is quite well known in the software world. It's photo editing capabilities rival those of commercial tools like Adobe Photoshop and Corel Painter, so much that many professional graphic designers use GIMP instead of it's expensive counterparts.
Operating systems supported: Windows, Mac OS X, Linux, FreeBSD and Solaris
Audacity is an audio editing and recording software. It has tools comparable to those of many professional audio programs, but it's free of course.
Operating systems supported: Windows, Mac OS X, Linux and BSD
This open source web browser is another prominent figure in the computer world. It features a sleek and efficient design coupled with loads of options.
Operating systems supported: Windows, Mac OS X, Linux, BSD and Solaris
***Windows only***
If you're like me and you enjoy downloading tons of programs onto your computer, then you've surely come across files compressed in strange formats such as *.rar, *.ace, *.tar.gz, *.bzip2, etc. Naturally, these files can't be extracted by the standard windows extractor tool, and you'll need to install a third party program. This is where Universal Extractor gets handy. With this piece of software, you can extract just about any compressed file out there, even installers! The program simply adds a few "Uniextract" options to the context menu of supported files and that's about it! It works flawlessly and is free.
A media player that plays everything... that's VLC. Indeed, VLC will plays any audio, video and dvd format. Unfortunately though, there's still no native blu ray support, but add-on codecs exist.
Operating systems supported: WIndows, Mac OS X, Linux, Solaris, BeOS and BSD
***Linux only***
I would have ranked Kdenlive higher if it had been available on Windows and/or Mac. Other than that, I have absolutely no complaints against it. But what is Kdenlive? Well, Kdenlive is basically a video editor/creator that's almost as powerful as Adobe Premiere, but a lot simpler to use. For hobbyist video producers, you won't believe that this is free, the quantity and quality of the options being overwhelming.
Here's one that you may have heard about. Blender is a program to create 3d models and animations. It's probably worth over a hundred dollars, but in their incredible generosity, the developpers that created Blender released it under the GNU GPL license, subsequent to a funding campaign. Overall, even if 3d modelling isn't your speciality, you still might want to try Blender, it's just so much fun!
Operating systems supported: Windows, Mac OS X, Linux, Solaris and Irix
Ok, this is a strange one. The GNU Compiler Collection is a set of tools to create your OWN programs. They are quite complicated to use and require you to learn a programming language (this is quite time consuming). Now the reason I put this so high on my list is quite simple: most of the free programs out there have been written using GCC. Chances are you'll never use it, but keep in mind it's incredible contribution to the software world.
Operating systems supported: Just about all of them
Here's probably the most popular free program (well, programs actually) ever made. Open Office is the office suite to end all office suites. It has just about as many functions as Microsoft Office, but with a little difference... it's free of course. That's about all I have to says about Open Office There's no reason to complain, this program is just perfect.
Yup, Linux is our big winner. With this kernel and a few other programs, you can get a full fledged computer operating system for FREE. No more need to pay a hundred dollars to buy the newest version of Windows! Of course, if you don't want to build your own Linux, just download a prebuilt distribution like Ubuntu, Linux Mint, Fedora, Puppy Linux, etc.