I started to work and play with computers on my father's Schneider CPC464, which I later used completely on my own when he bought his first PC, an IBM compatible PC XT. There I made my first experiences with DOS (in particular, MS-DOS and DR-DOS). Later I had my own PC with a 80386 SX main processor, operated by DOS and Windows 3.1. This was followed by a 80486 PC, which I used for a long time (I think up until 1999), and the OS/2 operating system.
I still have a Pentium III PC at home which I used, e.g., to initially create this website. From 2000 on, I only use the Linux operating system on my PCs. For few exceptions, I had a Windows 2000 machine (e.g., for programs I have developed for my diploma thesis).
At work I used to have a Thinkpad T41p notebook with Linux running on it. The main reason for that device was that it had a TPM chip on it. Since I worked with many operating systems due to my research in operating system security, I also had Windows Vista and OpenSolaris as well as experimental operating systems like Turaya (an L4 microkernel based system) on my machine.
For several years at home, and at work in university from 2010 to 2014, I have used Apple Mac computers. The list of devices I used to work with range from a white iMac and a white MacBook with Intel Core2Duo processors up to more recent iMacs, MacBookPro, and iPhone and iPad, of course.
A little anecdote on Mac and security:
During my PhD defense I was asked why I use a Mac as it does not have a TPM to support trusted computing functionality. My answer was that the usability of the device and its OS X operating systems outperforms the missing security of the TPM. But who knows, maybe the Macs will support trusted computing in the future. :-)