Yeah, I'm using an nVidia driver also. There's nothing like playing Doom 3 and Unreal Tournament 2004 on Linux. <3

Also, try to keep in mind that Linux's goal isn't to dominate the desktop market, rather it's goal is to provide an alternative. Different OS's provide different functionality. People use Windows because it's relatively easy to learn and use. People use Linux because they like the freedom of being able to "get under the hood" of their operating system. This is probably the main reason Linux will never take over the desktop market.

Well, it depends on your situation, really. If you're still relatively young and haven't had any or many jobs yet, an "Internship" can look good on a resumé.