Which tax system (Progressive, Regressive, or Proportional) do you find to be the fairest and why?

Income $50,000 100,000 200,000 Proportional Tax Amount Percent of Tax of Income $12,500 25% 25,000 25 50,000 25 Regressive Tax Amount Percent of Tax of Income $15,000 30% 25,000 25 40,000 20 Progressive Tax Amount Percent of Tax of Income $10,000 20% 25,000 25 60,000 30