Easily NFL
I like the NFL because its one and done. If you have a bad game then you lose and have to make it up next year. No ifs, ands or buts.
NBA is WOAT because the 1st round is 7 games. Who wants to watch a 7 game series between the #1 team and the #8 team? Even the #4 vs #5 team is boring. I know the NBA makes a lot of money in the playoffs by extending the playoffs, but it would be better if they did it like this;
1st round - 1 game
2nd round - 3 games
3rd round - 5 games
Finals - 7 games
Granted, they wouldn't make as much money, but it would be more exciting. A team could upset the #1 team in the 1st round and that would change everything.