Recommendations for operating system

[Choctaw Bob]

I think that this just squeaks in as being on topic.

I am looking for suggestions for an operating system for a PC, specs 75 
MHZ Pentium, 16 MB Ram, 4 GB HD, currently running PC-DOS Ver 7.  
Original IBM PC-DOS right out of the factory sealed box.  I am thinking 
about  putting GEM on the machine, maybe CP/M-86.  Thought about GEOS, 
but rejected it, too closed. 
Specs seem too tight for Linux or BSD, or at least little advantage over 
DOS or CP/M.

Anyone have experience with an operating system that might work, and be 
capable of useful work?