<p>DirectX <em>is</em> popular for game development…on Windows machines. And DirectX is, by all accounts, much better than it used to be, so I’m not discouraging anybody from using it. However, I have to point out that the universal graphics library, OpenGL, is a more widely supported standard in terms of number of platforms–you’ll find it on the PS3, the Wii, mobile gaming, and yes, even the Windows PC. And I imagine that 99% of computer graphics classes use OpenGL and Linux, for simplicity (MS keeps adding more baggage–I mean technology–to Windows software development) and cost. If you want to do CG as a career (and who doesn’t!) you NEED OpenGL. High-end graphics work is often done on Linux/UNIX, especially render farms. No DirectX there.</p>