My first "computer" was a Commodore my mother was borrowing from the school board.
My first PC was an 8088. This would have been 1988. I was running DOS 3.0 IIRC. I later upgraded it to DOS 5.0, then 6.0, then 6.2, and then 6.22. I still have the disks. I also had Windows 2.0 at one point, and Windows 3.0.
I then ended up with an IBM 486 SX/25. I ran Windows 3.1, then WFWG, 3.11. I replaced it with FreeBSD. Then Slackware Linux. Then FreeBSD again. Then Windows 95, then FreeBSD, then 95B.
I then had a Texas Instruments Travelmate Notebook, 2MB of RAM, that I ran Windows 3.11 on. I installed Windows 95 on it from floppies. I still had the desktop at this time as well.
I was in grade 9 at this point, and began taking computer courses at the local University my dad was teaching at. Systems I had access to, and used, were some DEC ALPHA boxes, a 486 running OS/2 Warp, and a few HP-UX systems.
My 486 desktop was upgraded to 48MB of RAM and a 1.6GB hard drive. I was a beta tester for Microsoft, and it was my Windows 98 beta test box. After Windows 98 testing was complete, it ended up with FreeBSD on it again.
I then got a Toshiba 330CDT notebook. Pentium CPU at 266Mhz and 64MB of RAM. It came with Windows 98SE on it. It then got FreeBSD. And then it got Redhat Linux. And then I started beta testing NT5.0, so it got that. I still had my 486, which was back to running FreeBSD and operated as a firewall and test box.
Through the NT5 testing and subsequent renaming to Windows 2000, I dabbled with more Redhat and FreeBSD.
I was then the "bad" guy in my MCSE class that installed RedHat and Mandrake on my classroom PC. At this time I got to play with IRIX quite a bit.
Since that point, I've had far too many systems to list. I've done Yellowdog Linux on my MAC notebook, Hackintosh (OSX) on a couple of systems, and run FreeBSD, OpenBSD, NetBSD, Suse, Solaris, Gentoo, Ubuntu, Kubuntu, RHEL, Fedora, Slackware (current), Windows Vista, XP-64, XP, Vista-64, 7-beta's and RC, 7 64 (current), Mandrake, Lindows, BeOS, OpenSolaris, Sabayon...etc. As well as a good sized list of firewall distro's.
Browser choice over the years has been everything from Mosaic and Lynx through the original IE, then Netscape, Opera, Mozilla, Firefox, Chrome, all the IE iterations and a few goofy ones that no longer exist.