Communism is a nice theory on paper and probably can work alright in small groups, but I don't see it working in a modern world with a large population. There's too many inefficiencies and problems that arise.
Some form of a well regulated free market with solid social programs for citizens along with a democratic setup works best.
Maybe some version of it in a Star Trek like future where humanity is more invested in space travel and we have things like replicators, we'll have a post-capitalist world, but that's probably a few hundred years off.