If I had to sort the OS that I have used by how much I like them I think that I would end up with this list:
not run old MS-DOS applications and especially games!
Thankfully some guys made DosBox so that everybody can play his/her favorite old-fashioned games. DosBox is a free, complete Intel x86 PC emulator; it emulates the CPU, the graphics card, the sound card and supports joystick, mouse and many other things! It is open source and free software and will run on Linux and Windows. To play a game simply mount a directory as a drive in DosBox but I won't tell you how to do this. Instead go to this page to download DosBox and then visit the Wiki for more information on how to use the program.
- Backup the configuration file and edit it. Learn all options and try all of them! Check this page for more info. You can achieve great results by messing up with the configuration file.
- Find Heretic - Shadow of the Serpent Riders, Descent I, Blake Stone and Doom. Play them. ;-)