Forbes' ranks the top 10 most valuable sports teams 10) Washington Redskins $2.95 billion 9) San Francisco 49ersLos Angeles Lakers $3 billion 8) New York Giants $3.1 billion 7) New York Knicks $3.3 billion 6) New England Patriots $3.4 billion 5) Real Madrid $3.58 billion 4) Barcelona $3.64 billion 3) Manchester United $3.69 billion 2) New York Yankees $3.7 billion 1) Dallas Cowboys $4.