At a first glance, American football is closer to rugby league than rugby union, as play stops/pauses after each tackle and there is a limited number of tackles/downs allowed before a turnover is enforced (although in American football, the count resets if the attacking team advances over ten yards).

However, American football is similar to rugby union in that different positions require different kinds of athletes (big fatties at hooker/prop, speedsters at wing, quicking-thinking agile guy at scrum half etc.).

But then American football is closer to cricket when it comes to tactics and the amount of time required between plays.

In the end, though, I find Australian football the best game to watch. It's flowing, the players are incredible athletes and it's pretty high scoring. Also, because of the draft and salary cap, you don't get the Manchester Uniteds, Arsenals and Liverpools who almost always finish near the top of the table. Every team has its day.