I don't see Carmelo as the best scorer in the league, either, certainly not the most efficient. Anybody that takes as many shots as he does should be averaging arounf 28 ppg, instead of his 23.8. Only Kobe Bryant has missed more shots than Carmelo, and they are a close 1 - 2.
As for efficiency as scorers, I would go with LeBron, Dwight Howard, Gortat, Blake Griffin, Bosh, Andrew Bynum, LaMarcus Aldridge, Boozer, Steve Nash, Durant.
Carmelo's also having a tough year with 3-pointers. Best three point shooters to date are Ray Allen, Ryan Anderson, Richard Jefferson, Mario Chalmers, Paul George, Turkoglu, Redick, Pearce, Chris Paul, OJ Mayo.
Melo's taken 83 3-pointers. The average NBA player taking 83 would have hit 31 of them; Carmelo's hit 25.