I don't know why this subject always causes so much heated emotions. Not to say soccer is the greatest sport or anything, but it's the superior sport when it comes to worldwide popularity. It's ridiculous to even compare other sports to it.
Soccer is played all around the world, by BILLIONS of people. American football, which actually originated from European rugby... imported to the US by British soldiers... is virtually non-existant sport outside the US. The only international North American based sports are ice hockey and basketball, but neither of them can be compared to popularity of soccer, which is played everywhere (Africa, Asia, India, etc.)
World Cup is the biggest sport event in the world, hands down... and it's viewed by BILLIONS of people. The soccer stars are truly world famous... and I doubt an average European/Asian/African could name even ONE American football/baseball player by name. With the exception of Japan, where they play baseball (I think).
Funny thing... despite being played all around the world, there has never been a World Cup final without one of these four countries:
Italy
Argentina
Brazil
Germany
The "big four" have won multiple championships and besides them, only France and England once (and Uruguay in the 30'S) have managed to win the World Cup. Only 7 countries total!!!