At 44-13, the Houston Rockets are a half game ahead of Golden State and hold the best record in the NBA.
After the additions of Joe Johnson and Brandan Wright, Houston has become arguably the deepest team in the league. Eric Gordon, Gerald Green and Ryan Anderson gives Houston plenty of scoring punch off of the bench. And of course, James Harden and Chris Paul can carry a team offensively by themselves.
Although, the biggest difference for the Rockets has probably been their defense.