If it's something I never intend to play again then I'll sell it unless it's worth next to nothing then I'll keep it. I still have my SNES, PS2, PS3
Only thing I ever got rid of that I really regret was my translucent green N64 with the limited edition Donkey Kong banana controller and boy oh boy do I regret that. At the time I really wanted money for a Playstation and had no other options.
It's cool to have the physical copies of stuff but emulation has came so far that there's almost nothing I can't play on my PC that I want to play aside from a handful of PS3 games that don't play right yet