Well considering no country is completely a capitalist economy, there are numerous alternatives. The closest thing to capitalism would be Singapore or Hong Kong, so I assume you mean alternatives to that. Most countries are mixed economies.
In my opinion the Nordic Model, meaning styles used by Norway, Sweden, Finland and other Nordic nations works very well. It is characterized by little government interference and no government ownership in the private sector. Also it has a large social welfare net with many nationalized sectors such as health care. The countries may not have as high of a GDP per capita as say the U.S. or Hong Kong, but the people have long life spans, polls and statistics show people are very happy in those countries and they are prosperous.
That's my opinion, and what I would advocate based on what I have seen and read. However, people would argue that capital in those countries could be allocated better by the private sector if it wasn't for such high taxes, and that the countries aren't as efficient as they could be. But, I think that's a reasonable cost to the lifestyle and economic strength of those countries.