I use a lot of software and websites every day, and I want to share some good and free tools with you.
Game development
A good tool to start with if you want to program games is Game Maker. I also learnt to program with it. Game Maker
Once Game Maker is not enough anymore and you decide to move to C++ or C#, Micro$oft Visual Studio is the tool to use. That's right, Microsoft also has good software. They even offer free versions of each package (C++, C#, VB.NET). Visual Studio Express Editions
For 3D design, whether you are making low-poly models for a game or rendering a high-poly cutscene, Blender is the way to go. Blender.
Of course, when you have all those nice 3D models, you need some textures for them. MaPZone is the right tool for this job. MaPZone
To render all this content, you can use OGRE. It's a very good 3D rendering library that works cross-platform. OGRE
To get some things moving in your game, use Bullet. There are many good free physics engines out there but Bullet is the best. Bullet
L3DT generates a nice terrain for you. It's by far the best and most extensive tool I've found, but only the basic version is free, though that's more than enough for most purposes. L3DT
EuclideanSpace is a website with a lot of information about mathematical objects with the focus on programming, and some other programming/math/physics related topics as well. EuclideanSpace
General Programming
IcoFX is a great free icon editor. Though it also features some basic functionality like Paint, I create my icons in Photoshop and use IcoFX to put them together in a .ico file. IcoFX
To generate some documentation from your source code, Doxygen is by far the best tool. Doxygen
Inno Setup packs your software together in an installer. I find it easier to use than NSIS. Inno Setup
I have used many web development IDEs, but Komodo Edit is—by far—the best. I started with Adobe GoLive for the first version of my site. Then Adobe acquired Macromedia and they discontinued GoLive so I switched to Dreamweaver. I did not like Dreamweaver very much but at the time I still did WYSIWYG design. Then I switched to Microsoft Expression Web. Expression was much better as it allowed previewing PHP files without a server. Now I use a personal testing server, so I don't have to worry about that. Komodo Edit has some preview features but I don't use them. The main thing about Komodo Edit I like is that it highlights virtually every language you can think of. It also offers the best intellisense of all IDEs I have used. Dreamweaver has virtually none; it fails when things get a little complex. Expression Web did a better job but still failed at many points. Komodo Edit is the best at this point. It also has support for Javascript libraries like jQuery. I edit my files directly at the server mounted as a drive. Komodo can connect to a server via SFTP, something only few programs can. There also is a paid professional version but you probably won't need it. Komodo Edit
Other links
Inkscape simply is the best vector editing program available. I use both Inkscape and Adobe Illustrator, and Inkscape beats Illustrator. Inkscape
Ubuntu is the most user-friendly version of Linux. A lot of the tools mentioned above (Blender, Inkscape, Komodo Edit, …), are also available for Ubuntu. It can run from a CD without ever installing. Also useful for repairing broken PCs. Ubuntu
Wolfram|Alpha knows everything. Wolfram|Alpha
A List Apart has a lot of interesting articles about web design. A List Apart
