First of all, the reason your gamer friends like Linux isn't because it is good for games: it's because most geeks are also gamers. Geeks love Linux because it is much better than Windows on hundreds of points. It is more stable, easier to configure (as in more configs availible, not ease of doing it), it's open source, and a million other reasons.
Linux controls aprox. 60% of the server market. What does that tell you? It tells you it is reliable and secure! People don't trust buggy software with their data. The reason that most games are written for Windows rather than Linux is simply because that is where the demand is currently. If people would start insisting that games be Linux compatible, it would happen. The biggest compatability issue is whether the game is written with DirectX or OpenGL. OpenGL is open source and runs great in both Windows AND Linux! In fact, it often outperforms DirectX in system benchmark tests. Great games, such as Neverwinter Nights, have been written using openGL and they do run fine in Linux. But sadly, that is not the majority.
My suggestion is to put Linux on your computer and give it a shot. As mentioned above, there is GREAT Linux software availible for Office, editing, video, cd burning, finances (gnucash rocks my socks off!), and they are all FREE! (Thank you GPL!). The best way to learn is to dive in and get your whole body wet. Force yourself to write papers in Openoffice Writer rather than MS Word. Do your photo editting in Gimp rather than Photoshop. You'll learn quickly because you want to be able to do your work. Anyway, that should give you a good overview.