I love Linux. I run a web/ftp/SSH/what-have-you server with it, and I also have a Linux box that function as a router for my house.
With that said, I don't think Linux is nearly as good a desktop operating system as Windows. Software-wise, it's lacking in games, office suites, and professional tools. Hardware-wise, while it supports quite a lot, it doesn't support as much as Windows. For example -- try finding drivers for parallel port scanners. I've never seen any manufacturer drivers -- I know of a page that has reverse-engineered drivers that work with some scanners, but not perfectly, and not with mine. Try finding a high-quality button configuration editor for any gamepad or joystick. Or a capable DVD-playing program. USB support is still flakey -- sure, you can get it to work perfectly with days upon days of tweaking, but in Windows I can plug a USB device in and it works right away.
Also try finding a desktop GUI that is robust, fast, and pretty. KDE and Gnome both fit the first criteria -- but, at least IMO, Gnome fails the second and KDE fails the third. I wouldn't mind KDE being pretty if the designers actually studied interface design (well, they may have, but it doesn't show). For example, in Windows, if I snap my mouse to the lower-left and press a button, it opens the start menu. To the upper-right closes a window. Upper-left brings a menu of other window options. Lower-right goes to the systray. In KDE, however, after doing any of those things, you have to adjust your mouse away from the edge by a few pixels in order to actually hit the button -- that's a serious flaw, and costs me a lot of time in the long run.
But, anyways... This ended up taking longer than I intended, and this is hardly the place for an OS debate, so I'll stop. But for now, my personal computer is still running XP. ;-p