Coldspur: mteal was referring to a different packaging of the "restored" version. It's not the "45th Anniversary" version, but the complete cut. The "original" cut of Macbeth is nowhere near as good as the restored one. I only have the 45th Anniversary version on laserdisc, and I think it looks quite good.
For years, only the "original" version of Othello was available, and it made the movie appear as a laughably bad quickie flick. Not only did the studio replace the Scots accents (not everyone's were replaced, but most were), but the film was cut by 15 or so minutes. For a film that had already cut away much of Shakespeare's shortest play, that was an extreme cut. Jeanette Nolan's Lady Macbeth suffered most in the re-dub. While Scottish accents are certainly not needed for a production of Macbeth, they seemed to give the actors something to bite into, and added to the blood-and-thunder-melodrama style of the movie.
The only loss from the original version was a brief spoken introduction by Welles, which I wish had stayed in the restored cut.
Also, I was watching the film recently, and noticed that one line of Macbeth's was shortened in the restored cut. In the original version, in Banquo's and Macbeth's first scene with the witches, Macbeth has the the line "Stay, you imperfect speakers-tell me more! By Sinel's death, I know I am Thane of Glamis, but how of Cawdor?" In the resored version, the part of the line that includes By Sinel's death is omitted, whereas it is in the original version. So, Macbeth says "Stay, you imperfect speakers-tell me more! I know I am Thane of Glamis, but how of Cawdor?" It's no big deal, but kind of puzzling.