I've been recently debating with coworkers the merits and demerits of each OS. My coworkers are adamant Windows users while I'm pretty much an Apple convert. I'm curious tho what most devs use and why. So like I said, I prefer to use Mac OS X mainly because of ease of use, Unix-based, great hardware (although that's not really OS specific), and because overall (imo) it seems to be of better quality than most of the Windows systems I've used (I used to be a Windows only type guy at one point).
What about you guys?