DISC ONE & TWO
These are the two discs from the Superbit release, which contains superior video and audio.
DISC THREE & FOUR
The original 2-disc Limited Edition. Though the video quality is inferior to the Superbit's it's still worth owning for it's wealth of DVD-ROM content and supplemental content on disc two.
DISC FIVE
The "A Dangerous Man: Lawrence After Arabia" film, starring Ralph Fiennes as T.E. Lawrence.
DISC SIX
The PBS documentary, "Lawrence of Arabia: Battle for the Arab World".