Rocky III is my favorite Rocky film, and I can't count the number of times I've watched this one.
Stallone had to endure a lot in Rocky III. He had to deal with Mickey's tragic death, and Clubber Lang proved to be a real test for Rocky. Rocky fell into a comfort zone in this film, and he didn't have the same fire he had before, but the ass whipping he received from Lang proved to be the wake up call he desperately needed. Rocky didn't believe in himself anymore, but this passionate speech from Adrian gave him a huge boost:
http://www.youtube.com/watch?v=cz6oxIlmw_M
This is probably my favorite Rocky scene of all time. Rocky needed to regain his confidence, and this speech fueled the fire. Adrian was so strong, and she refused to let Rocky off of the hook. She forced the truth out of him, and she wasn't going to let him pass with a half ass answer.
Mr. T was so intimidating and mean, and he was VERY believable, as the hungry and scary fighter who wanted the top spot. Rocky had to overcome his fears, and he managed to defeat Lang in the last fight. The fight was awesome, because Stallone did such a great job of showing anger, as Lang was trying to beat his brains out. Rocky took out his toughest foe, and at the end of the film, he reclaimed his spot as the #1 guy.
Rocky III is easily a 10/10 for me, and I can watch this film over and over again. The story here is excellent, and the fight scenes are pretty brutal. Oh, and it's always fun to watch Thunderlips (Hulk Hogan) take on Rocky in that wild wrestling match/fight.