Sokudo Ningyou said:

The one thing that has bugged me since the EU and prequels established "Darth" as a title, not a name: editing out Obi-Wan's constant use of it during the final duel and replacing it with "Vader." To me, at least, it's a glaring continuity error, and annoying even in context with the other two original movies, as everyone uses "Vader" when not using his full title.

My head is spinning at the notion that something coming a long time afterwards serves to "establish". Don't get me wrong, I understand what you are saying, and it makes sense. But that's what drives me nuts about this whole Star Wars mess that Lucas has ended up creating.

Anyhow, in SW77 he's on a first-name basis with his former pupil, so continues to call him "Darth" as he always had. Even if the OT progressed based on the original story (DV and Anakin are 2 separate persons), it would make sense in the next films if everyone called him "Vader" since they weren't on a first-name basis with him.

Frankly, if you are trying to create continuity with the PT, it doesn't make sense for Obi-Wan to call him "Darth" or "Vader". He would have called him "Anakin". If you're watching the films 4-6,1-3 this name would be meaningless to the viewer unless in the hut scene Ben tells Luke "he betrayed and murdered Anakin, your father". In which case the duel serves as the reveal of Vader as Luke's father and then many other things are messed up in Empire. He could call him "Anakin" in that scene if the films are to be watched 1-6. But do people really do that?? I mean, what is one to think when they get to ANH and hear Ben tell Luke of his father's death? Again, my head is spinning.

I'm no longer sure what I set out to type here, but I am sure of something. The best order in which to watch the Star Wars saga is 4-5-6. The end. :D