well, i would quite like to get windows 3.11 and run it over the top of freedos.
As to what OS you can run on an old machine, i'm not sure what versions, but i heard linux was pretty resourceful on minimal hardware, of course you won't get it to be superflash by today's standards, anybody elaborate on this?
Also, X11 was going on about an implementation of the X11 graphical environment which runs on DOS, so you could get FreeDOS, or OpenDOS, both of which are opensource projects made with an aim to being binary compatible with M$DOS, and then you could get this X11 port and run it over the top, for a totally M$ free graphical computing experience post to say how you get on with it, because i for one would be interested to know...