Choices "right" and "wrong" abound within the Star Wars. In fact you could say the choice of dark or light is the underlying theme of the entire series. We ourselves make choices every day, big and small, that have long standing consequences for us and those around us. Our choices are made possible by the greatest gift besides life itself, Free Will.

The prequels showed us the far reaching choices of Anakin, the jedi, and the Republic. The original trilogy brought the choices of the children of Anakin, the Rebels, the Empire, the conflicted Vader and all associations inbetween. Each choice made had some impact on the later events of the saga.

Episode I - III
We start with the individual decisions which would bring the major players and groups together. The blockade and attack of Naboo which led to the Jedi involvement. The Jedi running into the Gungans and the rescue of Padme. Their subsequent choice of landing on Tatooine for repairs which led to the finding of Anakin in Watto's shop and his leaving his mother and the only life he ever knew. Problems within the senate which led Palpatine's rise. The Jedi's choices in regarding Anakin to the death of Qui-gon and Obi-wan taking Anakin as his Padawan.

We go on to Dooku becoming Sith. Padme becoming a senator. The jedi assigning Anakin as her protector which of course leads to them falling in love and secretly marrying. The creation of the clones and the choice of the Jedi and the Republic using them as an army. Anakin and Padme's choice to go after Obi-wan, etc. etc.

The third episode gives us the pregnancy of Padme, Anakin's fall to the dark side, The Jedi's destruction, and the rise of the Empire. Finally we have the hiding of the twins from Vader and the Emperor.

Stay with me now I'm going somewhere with this.

Episode IV - VI
We now find the choices of Leia and the rebellion bring in the involvement of Luke, Obi-wan, Han and Chewie. Ben decides to sacrifice himself. they rescue Leia, Luke joins the rebellion. Han decides to come back and they destroy the Death Star.

The attack on Hoth and the escape leads to the trip to Bespin and Han's carbon freezing. Luke goes to Dagobah and Yoda teaches him but he leaves before he's ready and meets up with Vader and finds out the truth.

Finally in ROTJ we have Han's rescue, Yoda giving Luke his final instructions, and the attack on the new Death Star. The Ewoks joining the ground assault. Luke's telling Leia the truth and his eventually successful attempt to help his father and the Emporers failed plans.

Cause and Effect
All of these choices led to other choices and so on. Like the proverbial butterfly flapping its' wings, any one choice made differently would have effected later events Changing them or making them completely null & void. We all wonder sometimes what would have happened if we done something differently. Had we said this or had we turned left instead of right we could have avoided this or that outcome. While in this world we can't change what was but do we just accept our choices as the end or do we learn something from them and make a better self.

Redemption
Vader/Anakin learned this from Luke. The last trial before becoming the Master he had long pined over. Gaining back in that instant everything he had lost so many years before. None of this would have been possible had Luke not shown him through his choice to throw down his lightsaber that he had the free will to make a new choice. The choice to not be who he had let himself become. the choice of redemption. Did it negate all the atrocities he had done? No, but it gave him the ability to move on and to grow. Vader had gone along with Palpatine all that time because he felt himself trapped in what he had done and had no choice in the matter. The wheel kept turning but he couldn't get out from under it. We've probably all felt like that at times to some degree.

We can choose to live in Hell but when we realize this doesn't have to be, Heaven is just another choice away. The past doesn't matter, and the future is nonexsistant. All there is, the ever present moment of now. We create this through the choices we make. It's up to our own free will. Under this rule even the worst person can find Heaven and the best can become lost.

Change is the only constant in the universe. Vader only had to realize he had the power to make it himself and become Anakin again. The redemption came not because Luke forgave his father, but because Anakin chose to forgive himself.

If you've made it this far, Thanks and May the Force be With You!

(edit)
I was in a hurry writing this at work and forgot a plug I was going to give. I just got home and sat down to add it. I was reading this excellent blog by Lord_Noctifer http://blogs.starwars.com/Ramblings_of_Morpheus/5 which was about similarities and differences in the Jedi and Sith.This line (see below) jumped out at me and had me thinking about free will and some new age philosophies mostly dealing with what comes after death and how that applied to that SW situation.
3. He started down the dark path as I have, but he stopped. He turned back....Hey, maybe there is hope for me!