Interesting information...

[TheDarthVader]

I found this information in a Lucasfilm licensed book, the Star Wars Movie Trilogy Sourcebook. This is a cool book and has write-ups about the characters. Here is what I found.
Jan Dodonna-- "Dodonna was one of the finest Star Destroyer captains during the days of the Old Republic.
Emperor--"...his old enemy, Mon Mothma". "The Emperor's plans may have reached further back in time than anyone could possibly imagine, for his ability to foresee the future was astounding. Perhaps the Emperor did not destroy [Kenobi] with the rest of the jedi because he foresaw the old man taking young Luke under his wing someday in the distant future. Obi-Wan had failed once and created Darth Vader, the Emperor's greatest servant." Perhaps he also saw Luke's envolvement in the destruction of the death star and knew that this action could create overconfidence in his new found power and that would cause him to make a mistake. <---edited
Owen and Beru---"Young Luke grew up believing that Owen and Beru were his aunt and uncle, but Owen was actually Obi-Wan Kenobi's brother".
Obi-Wan--" Kenobi knew that he could do more to bring freedom to the galaxy by guarding [Luke] than by leading a desperate battle, doomed to failure".
Tarkin--"...who formulated the infamous Tarkin Doctrine of rule through fear..."
Mon Mothma--" This extraordinary woman was one of the original architects of the rebellion, and, to this day, remains its leader and guide. As a member of the imperial senate, Mothma fought to retain whatever basic freedoms the beings of the galaxy had left, as the corrupt Palpatine stripped them away, one by one. The senate was torn, divided, and corrupt, easy prey to palpatine's manipulations, and unwilling to listen to "prophets of doom" like Mothma. And so it was that this visionary leader was forced to take her fight underground.
Crix Madine--"...was an imperial officer in charge of an elite army commando unit."

I am not sure how much of this is supposed to be "cannon" but it all sounds good to me. I thought I'd post to give some insight on Episode III.

[scruffziller]

Mmmmmmmmm very deep indeed.

[Jargo]

Former Imperials? disenfranchised. defecting to the rebellion, I suppose that would work. There'd have to be some sort of catalyst moment wouldn't there. i doubt they just turned up with their resume and applied for the jobs of rebellion cell leaders.

The Tarkin doctrine of rule through fear. I'd like to see that expounded upon.

And the Obi-Wan/Owen thing as we know has been altered. They aren't related but Anakin and Owen are which makes the line about owen warning Anakin not to go off and fight in the clone wars all the more poignant. He finds out he has Half brother and that he's quite cool and then he wants to go get himself killed fighting for 'a lost cause' as owen sees it. It definately works better with Anakin and Owen being related. Well from my POV it does anyway.

Palpatine as the evil sourcerer having engineered the whole thing with kenobi works too. I'm wondering if Lucas had read LOTR when he was writing SW originally. There are definately parallels that can be drawn between the two stories because they both follow the classic storyline and both use classical imagery to illustrate the hero's journey. Palpatine as Saruman is easy to see. Or at least the roles of both are very similar.
I hadn't thought about this until I watched LOTR the other day for the first time. Of course Saruman and palpatine are both different characters within their respective stories but the basics of their purpose within the stories are similar. If you look at Sauron as being the same as the Sith Lords from thousands of years ago then Saruman and Palpatine do start to look similar in storyline function. Maybe that's just me though. And i know I'm digressing slightly. But the whole backstory to the characters throws up some interesting points and analogies can be drawn that give clues as to where lucas drew his inspiration from. Perhaps not directly but maybe on a subconscious level. We know he was reading an awful lot of classic stories when he was researching the original ideas for star wars, he must have read frank herberts Dune and probably also Tolkiien's LOTR. It just makes the richness of star wars greater but also slightly diminished. IMO only.

[TheDarthVader]

I can see the relationship between star wars and lotr. It makes a lot of sense! Palpatine=Sauron His apprentice doing his will =Saruman and others that he controls indirectly=kenobi. That is quite a comparison but it makes sense.
Yes, I read that in the book (about kenobi and owen being brothers) and I am pretty sure Lucas just "changed his mind" and let Shmi marry Cleigg.
Do you think Owen knew that Vader was Luke's father?? Do you think Owen (like others) thought that Anakin had died?? It seems like Owen would know that Vader was Anakin because of the way he wants to hide everything from Luke.

[Jedi Clint]

Originally posted by TheDarthVader
Do you think Owen knew that Vader was Luke's father?? Do you think Owen (like others) thought that Anakin had died?? It seems like Owen would know that Vader was Anakin because of the way he wants to hide everything from Luke.

Owen knew something bad happened to Anakin. I think he'll get that info from Obi Wan when he brings Luke to stay with them.