Leaders of the G-20 group of industrial and emerging economies begin two days of talks in the Canadian city of Toronto later today. This gathering follows Friday's meeting of the G-8 group of wealthy nations in nearby Huntsville. Top of the agenda at both locations: the debate over whether governments should save or spend their way out of the ongoing financial crisis. And: differences over a possible bank levy and a tax on financial transactions -- both of which European leaders are pushing hard for.