For a high-quality 1080p Blu-ray encode (x264), you can typically expect:

: Each film includes four full-length audio commentaries from the director, writers, design team, production crew, and the lead cast. Production Depth

: Adds 51 minutes, including the iconic (and gruesome) confrontation with the Mouth of Sauron and the conclusion of Saruman’s arc Visuals: 1080p x264 vs. The "Green Tint"

The Lord of the Rings: The Motion Picture Trilogy (Extended Edition)

: Adds 44 minutes, featuring the tragic backstory of Boromir and Faramir The Return of the King

: Adds 30 minutes, including more of the Shire and the gift-giving in Lothlórien The Two Towers