Linux is basically for people who mostly want more security, more open source freedom and those that does not like windows os system because too many things to understand....
I prefer to use Linux myself, but there are some tasks that I have to keep going back to Windows to complete. I'm a developer, and though I'm increasingly developing in Java, the majority of the software I've written has been on .Net framework which is Windows.
I've heard you can use Mono for .Net development in Linux, but I haven't yet tried it out: when someone's breathing down your neck for code, you go with tried and true over need to test.
Linux, for me, really has strength in the resource usage. This is not a problem for most people (especially if you think it's normal to have to reboot frequently), but if you're skirting the edge with your system memory, you really don't have much room for tolerance. I've run full fledged distros of Linux on systems with only 256MB RAM without noticing much drag, but trying the same with an unhacked XP tends not to work so well.
Of course, if you're a serious gamer you'll have to use Windows eventually. By virtue of having most of the market, most major titles are coded for Windows and sometimes ported for Mac. True, you can use WINE to run *some* of the games, if you know how to configure it, but if your game doesn't run in WINE, then you need Windows.
My solution for gaming is to run a virtualized Win XP Pro from within Linux. Coincidentally, that's the way I do my home development in .Net, too.