Well I personally believe this is the last arc in the series (even though I would hate it to be).
good ending: Itachi reappears and talks sasuke out of vengeance, then sasuke ends up helping the allied ninja forces and they end up defeating madara, obito, kabuto, and the juubi. A time lapse occurs, naruto becomes hokage, but he isn't for all the paperwork so he leaves that to Sakura, who is now his assistant and sasuke now leads the Anbu black ops (more than likely not going to happen but we need to give him something and it's either that or life in prison for allying with the akatsuki and starting the war). The ninja world is now at peace and they all live happily ever after. Oh I almost forgot, naruto goes home to a pregnant Hinata where they will eventually live the happy life of a family.
Bad ending: The juubi continues to be out of control, so obito will try to take control but fails. Then obito and kakashi will end up having their battle and kakashi will surprising prevail and end obito with his lightning blade. Later the undead hokages will appear on the battlefield and all of them will regain their own self-conscious and all team up to fight madara. Once defeating him they will all fade away able to finally rest in peace. Tears will shed flash backs will happen blah blah, then leaves the juubi. Before appearing sasuke will find no more use for kabuto and end him quickly before entering the battlefield. Sasuke will then be able to take control of the juubi and him and naruto will finally have the battle of fate. After they fight for several chapters including flashbacks and all, naruto and sasuke will be short in chakra and only have enough to pull off one last jutsu, they will the. Do the classic chidori-rasengan collision and blast each other back both with fatal wounds. Sakura will then have to choose who she wants to save. Hesitant she decides to go to naruto because if kishi made her choose sasuke, all naruto fans out there would probably regret ever watching the show or reading the manga. Trying her hardest to save naruto's life, it just doesn't work. Leaving the village hero naruto and the only surviving uchiha member dead. This will leave a scar on everyone and they'll never forget the legacy. A time lapse will occur and we will see Sakura as hokage, living out naruto's dream and seeing the peaceful future through both naruto and sasuke.