Depends on what you count as a country and what you count as visiting...But at the moment, 55.
Europe: England, Scotland, Wales, Ireland, The Netherlands, Belgium, France, Czech Republic, Germany, Italy, Vatican City, Russia, Greece, Serbia, Latvia, Austria, Cyprus, Portugal, Turkey
Africa: Egypt
Asia: Japan, South Korea, Hong Kong, Singapore, Malaysia, Macau, Vietnam, Cambodia, China, Thailand, Malaysia, India, Taiwan, Israel, Palestine, Jordan, Lebanon
Oceania: Australia
North America: Canada, The United States of America, Mexico, Guatemala, Cuba, Belize, Honduras, El Salvador, Panama
South America: Colombia, Curacao, Venezuela, Peru, Ecuador, Chile, Argentina, Brazil, Uruguay
Hopefully I'm not missing anything.
This summer, I'm going to Brazil, Argentina, Paraguay, Chile, Bolivia, Mexico, Hong Kong, North Korea, China, Myanmar, Laos and The United States of America.
My total will be 60.