I started out as a Mac person, the day my dad brought home a 512k "fat mac". The last mac I bought for myself was a 233 MHz Beige G3. The last mac I bought (for my mom) was a ruby summer 2000 400 MHz iMac.
Shortly after buying the Beige G3 - I discovered the wonderful world of Linux. I bought a SCSI hard drive just so I could install MKLinux DR3 (A port of Red Hat Linux to the Mach Microkernel, the port was funded by Apple Computer).
Soon after that I took a few courses on Linux system administration and got a job as a Linux programmer, where I ran Linux on the x86 platform.
Currently I run Linux on an IBM Thinkpad T20, a home built x86 (built from spare parts and junked computers) and a home built x86_64 (built from new parts).
I will probably never buy another Mac, I do not like Apple's current company philosophy, they severely over charge for their hardware. I can build far more capable PCs than an iMac for about the price of an iMac, and while their pro towers are a decent deal for the hardware, they aren't what I need and I would rather spend that money by putting the money into parts that benefit me. I also disagree with their continual refusal to make the batteries of iPods and iPhones user replaceable.
Linux reduces techno-waste since you can find currently supported distributions that continue to run decently on old hardware.
Take my IBM Thinkpad for example. It is a Thinkpad T20 - 700MHz with 384MB of RAM.
It can not run Vista. I have run XP SP1 on it but it was painful. However, it runs CentOS 5.2 no problem. CentOS 5.2 (Red Hat Enterprise Linux clone) is the same distribution I run my other two computers and on my remote server.
Try running current MacOS or Windows on a computer built in 2000. When you can, it is extremely painful. As such, the constant updates to those major operating systems results in an increase in tech waste that is causing some serious environmental problems, as proper recycling of tech waste just isn't economical (most places that claim to recycle sell to a third party which takes the money and illegally dumps the tech in third world countries).
I guess I'm a PC guy because I technically use PC hardware, but other than laptops, I build the computers myself to my specifications. I do not, however, use Windows or Mac OS. I have not found anything I can not do in Linux other than play specific games, but I have a PS2 for that
I suppose if I needed advanced photo editing capabilities, I might need photoshop - which would require Windows or Mac OS - but for my photo editing needs, The GIMP does just fine.