Bottom line is money, NFL on average get paid the most.
According to the USA Today sports salary database linked below, the NFL team with the highest average salary is the 49ers at $1,325,000, The next closest team has an average under $1.1 million.
2009
Team Median Salary
San Francisco 49ers $ 1,325,000
Atlanta Falcons $ 1,050,780
Tennessee Titans $ 1,010,000
Philadelphia Eagles $ 1,003,530
Seattle Seahawks $ 1,003,495
Minnesota Vikings $ 952,665
USATODAY.com
The average English Premier League player currently makes around £1,100,000 which is $1,797,202.
In the Premier League, where no wage cap operates, the average player earns about £21,000 a week, or £1.1m a year
Premier League stars face fans' backlash over 'crazy' wages | Football | guardian.co.uk