Corrected entry: If C3-PO is from Tatooine and R2-D2 was there, why in Star Wars are they completely unfamiliar with the planet? How come R2-D2 doesn't know Obi-wan and Obi-wan doesn't recognise the robot that saved his life?
Corrected entry: When Senator Palpatine informs Amidala that he is a candidate for the Chairman, she asks who are the oponents. He answers: "...and Bail Antilles of Alderaan." Antilles (Wedge) was from Correlia, and Palpatine's greatest opposition was Bail Organa of Alderaan (Leia's father).
Correction: It's been explained that Antilles is a fairly common surname, and Bail is a relatively common first name, so the similarity is entirely coincidental.
Corrected entry: When Qui Gon first enters Watto's shop he is greeted by Watto in a language other than English (let's just abbreviate this language as OTE - Other Than English). Even though Qui Gon is greeted in OTE he then speaks English to Watto. This would indicate that he either understands OTE, or knows that Watto can also speak English. Watto then calls in Anakin and speaks to him in OTE. Yet he always speaks to Qui Gon in English. Even though Anakin and Watto speak both languages, they usually speak English to Qui Gon. Watto seems to speak OTE to Anakin whenever he doesn't want Qui Gon to understand him. However, in the scene where Qui Gon and Watto bet on the race there is a shot where Watto speaks to Anakin in OTE and the translation is something along the lines of "Better stop your friend's betting or I may end up owning him too." Then Anakin looks to Qui Gon and asks, "What did he mean by that?" Then Qui Gon replies, "I'll tell you later." This would indicate that Qui Gon understood what Watto had just said AND that he understands OTE.
Correction: The OTE language that Watto speaks is consistent with the Star Wars world - English being known as Basic - the common language. It can be assumed that senior jedi and businessmen know a variety of languages, OTE being something common in the Outer Rim like Huttese or whatever (if OTE were Watto's own language, and Qui-Gon were familiar, why is it he did not know Watto's resistance to the Force). So Qui-Gon would be familiar, but not proficient in such a language, while Basic would be the common language denominator.
Corrected entry: In the opening story text of The Phantom Menace, it refers to Obi-Wan and Qui Gon Jinn as Jedi knights- but Obi-Wan is still a padawan and not yet a Jedi knight.
Correction: He's a Jedi Knight in training and is ready for the trials. Close enough, particularly as the opening text must, by necessity, be brief.
Tailkinker
Correction: And Qui-Gon is a Jedi Master. Like the other correction said, it's for brevity during the opening crawl.
Corrected entry: When Obi-Wan is hanging on to the ledge when he fights Maul, he sees Qui-Gon's lightsaber on the ground next to him. The design of the hilt is the same as Obi-Wan's. No two Jedi have the same hilt design.
Correction: There's no rule stating that Jedi must have a unique design - Jedi build their own lightsabres using whatever design they see fit to use. There's nothing to prevent Obi-Wan from building one similar to his master's sabre.
Tailkinker 
Correction: In "A New Hope", Uncle Owen tells Luke to take R2-D2 to get its memory erased as if the memory erase isn't a big deal at all. Most likely, in the thirty or so years between episodes 1 and 4, an owner of the droids did exactly what Uncle Owen wanted to do. Also, Obi-Wan must have worked with hundreds of droids in his career as a Jedi - this may be disproved in the forthcoming films, but for the moment we can only assume that R2-D2 was one of many.