I switched in August '04, because I had to. I already decided that I really wanted to get into video editing, and that only happens on a Mac, really. However, I'm glad I switched. My sister got a 333 MHz iMac with System 8.6 for her fourteenth birthday, but she never used it, and I never used it that much, either. We got an iMac for my brother a year later, and still uses it today, and we also got an iMac for my other sister a year later, simply because we knew iMacs were great machines for college. However, my sister with the newest iMac dropped her necklace down it, and basically ruined the machine, for all we knew. She got a Dell Laptop two years after she got her iMac, and that Snow machine sat in the basement for a year until I switched, where I took it into the Geek Squad, and put on Mac OS 10.1. I used that as my first Mac, but this May, I had to get more serious about my editing than iMovie 3. That's when I got my current computer, the iMac G5, and I absolutely love it.
Anyways, I try not to force PC people into switching. It comes off geeky and rude, plus, we are the ones that know the best computers around, and if more PC people started using Macs, the virus risk would climb. Therefore, I keep Macs to myself, and to people who don't care what kind of machine they're using, I pretend like I'm one of them. It does wonders do your social life! Anyways, if somebody needs a new computer, I immediately tell them, politely though, to get a Mac.
I image myself staying an iMacZealot. In the words of a fellow poster, "I won't ever switch until I die, and you pluck my one-button mouse out of my cold, dead hands!"