I've posted this in one form or another before, but I consider myself a quasi-switcher in that my computing history has included both macs and pcs through the years.
My elementary school had a lab that contained only macs (mixed apple II and III). So we used those for our computers at school (Logo anyone?). In 1985 we got our first home computer: an Apple IIc back in the days of 200 baud modems and bbs boards. We used that until the late 80's when my grandpa gave us an old IBM clone when he bought a new computer for his business.
That IBM clone was replaced throughout the years by various PCs. At school, I would continue to admire the Macs for the hardware but became the typical mac-hater complaining about the OS (single button mouse, no software, lots of crashes, etc.). I graduated high school and went to college without my own computer. Thus, in order to use a computer I had to trek over to the lab. The enginering and business schools had primarily PC labs, but they were all the way across campus. The closest lab to me had a mix of pcs and macs (mainly LC and Classics). Of course, there was always a wait for the PCs but you could always get on the macs. So I used the macs. That lasted a semester at which point I pieced together my own PC and used that in the dorm. That PC was replaced by various other hand-me-down pcs during college. All the while, I continued to be envious of the great looking hardware that apple sold.
My parents bought me a Dell in 1998 as a graduation present (my personal first NEW computer). I used that for three years though law school. By the end of 2001 I started to hear about OS X and this new gadget they called an iPod. The iPod interested me, and I began to read more about it and OS X.
The next Christmas (2002), my brother-in-law brought his iBook and new iPod with him. I had the opportunity to play with both and was hooked. Plus, with everything I had read about OS X, I was sure it was right for me.
By the end of January 2002, I owned a G3 iBook -- even though the legal profession is essesntially dominated by the PC. I'm now using an new iBook G4 happily at my otherwise Windows only office. Thankfully we have a Citrix server so I can access the few PC only programs we have to use without running Virtual PC. I love the looks I get when I whip out the iBook in the company of other lawyers!
So, why did I switch? That uniquely Apple combination of great looking hardware coupled with the best OS on the market. I love that OS X is so simple and easy to use ("It just works") while also having all of the UNIX power behind it. It takes me back to the days of using the VAX in college!