In the beginning there was DOS, liked it very much, nowadays pure nostalgia, even bought the official IBM PC DOS 2000 CD, later on came Windows, liked 3.0, 3.11 for workgroups, 95 at first was iffy, it wanted 8MB RAM, the computer we had at that time had 4MB.. so for a while we tried OS/2 Warp 3, you could add parts of Widows 3.11 to it so it could run 3.11 programs.
Did switch to 95, when we bought a seriously fast Pentium 100 MHz machine with 16(!!!!) MB RAM, 98SE followed, that one was a great OS, used it on machines ranging from a K6 233 to a Pentium II 450, later on switched to Win2K which I used to the last day it was supported, skipped ME because I knew quite a few unhappy people who used it at that time, couldn't get along with XP at first but later on I came to like it, skipped Vista mostly, 7 was and is great, 8 was not bad with Classic Shell it was great, 8.1 I still use on the game rig, anything else runs Linux, started with OpenSUSE 11.xx , switched to Xubuntu 6.06 LTS and then to Linux Mint 13, since that day I've used Mint on all the laptops and desktops.
Still messing with the old Athlon64 X2 4800+ thing is a Brisbane core AM2 chip and it is quite the hot head, can't use a large cooler because of the tiny microtower, stock cooler did work but when pushed it would turn into a jet engine.. dug out a really old Thermaltake copper cooler, added a 80x80x25mm fan, Arctic F8 which runs at 2300RPM so at the moment while I'm typing this, idle temps are great for a chip of that kind, load temps also aren't bad both cores below 55c CPU temp itself below 46c not bad I would say, the machine is usable, can browse and youtube, will do 1080p but not 100% smoothly.