Lets see, there are so many reasons. I upgraded every major software component of my computer with out rebooting once (with the exception of the kernel. I only upgraded the header files). Just try to install a program in Windows and you'd be rebooting all over the place.

There are so many applications that come with it to increase productivity. Some notable ones are Dia, vim & latex , GtkGraph, Kdict (and Gdict), gftp, GIMP, GQView, StarOffice, GCC, Java, a hex editor, and many others. Just try to insert a graph of a function or a diagram of an electrical circuit into a Word file. You'd need some expensive programs to do so. Actually, in all fairness, I was able to find a shareware program that does graphs for Windows.

There are so many applications that come with it for every day use. Some of these programs are one of the many text editors (such as Kate, Gedit, vim), one of many web browsers (such as Konqueror, Mozilla, Netscape, Opera, Galeon, Lynx and Links), one of many html editors, chat programs, email programs, instant message programs, programs for running things like PDAs, scanners, and digital cameras, news reader programs (such as pan and knode), address books, calendars and too much more to list. There are even games, just not very many.

Don't like how the GUI looks or acts? Change it! Or you could just use another one. You aren't limited to one weak option. Never need SCSI support or FAT support? Just don't compile it into your kernel and it won't bog you down!

From personal experience, I've enjoyed more stability with Linux that I ever did with Windows. And, in the rare event that some part of my system acted up, I was able to quarantine the offending application and kill it with out disrupting the rest of the OS.

From personal experience, I haven't notices much speed difference between Windows and Linux. Starting IE 5.0 in Windows 98 takes about half the time as Konqueror in KDE 2.2.1. Starting StarOffice (5 or 6 beta) in Linux takes about 3/4 the time it takes in Windows. Windows boots much faster than Linux... and much more often

And Linux is prettier. The GUIs in Linux are much nicer than that of Windows. In fact, sometimes when I try to read things in Windows, they are so illegible because of the ugly jagged fonts that I have to print them out to read them. I don't have that problem in Linux and I have screen shots to prove it (I'd post them if I could find a place to upload the pics).

I like Linux for what it can do, not because of what Windows can't do. So that's my rant and my opinion. Feel free to tear it apart as you will.