What is the best NFL football team of all time?

It depends on how you measure 'best'.  If best refers to most Super Bowls won, then the Pittsburgh Steelers, New England Patriots, and San Francisco 49ers are the best teams.  If best refers to the team that scored the most points, then I would look up which team in which year scored the most points in a single season on NFL.com.  If best refers to my personal favorite team, then I would choose the Seattle Seahawks because that is where I grew up and first started loving football.