Give just those two choices I would pick Capitalism as being the most likely to reach its ideal at some point. Although ideal Capitalism would probably have a lot of the things that people where I live fear about Communism. And I mean some really minor things too, I was once in a sociology class where a dozen or so students got really pissed about the fact that fraud could be punished by the government.
If I could pick anything, I would probably go with some modern form of Socialism, obviously large Capitalist markets are unavoidable in anything remotely realistic but there are a lot of things I'd rather just be sure get done by someone than leave to markets.