I actually prefer the cinema releases, I feel they are better paced, and that a lot of the added stuff is kind of silly and superfluous.
I could not watch the theatrical cuts of the films now. I would miss all the bits added to the extended versions, the theatrical cuts are still great however.
I really like the the Mouth of Sauron, paths of the dead, the midgwater marshes. Aragorn using the palantir. Galadriel giving her gifts that are used later in the films. The death of Suruman. In fact there are so many that really add to the films imo, and some help explain the story better.
Here is a list of changes.
The Fellowship of the Ring
Bilbo's opening narration "Concerning Hobbits".
Bilbo at the party scene avoiding the Sackville-Bagginses.
Bilbo and Frodo's dialogue at the party scene, while avoiding the Sackville-Bagginses.
The Hobbits at the Green Dragon Inn.
A conversation between Ted Sandyman, Hamfast Gamgee, Old Noakes, Samwise Gamgee and Frodo Baggins.
Frodo and Sam seeing Wood Elves making their way to the Grey Havens on their first day of their journey across the Shire.
The crossing of the Midgewater.
Aragorn singing "The Lay of Lúthien".
Sam shows Frodo the trolls when they are at Trollshaws.
Gandalf reciting Black Speech at the Council of Elrond.
Aragorn visiting his mother's grave.
The Fellowship given a goodbye at Rivendell.
Gandalf warning Frodo about Boromir near Moria.
Lothlórien panorama added.
Sam's poem about Gandalf's fireworks.
The Fellowship members have flashbacks from when they were given their gifts from Galadriel.
Celeborn and Aragorn have a conversation in a flashback.
Aragorn and Boromir seeing Gollum behind a floating log.
More of Merry and Pippin defending Boromir at Amon Hen
The Two Towers
Sam using his Elvish Rope to help him and Frodo rapel down a cliff, and a clip in which it is raining on them.
Pippin believes that Merry is wounded and asks the uruk-hai to give him some water. Instead they give him orc draught to drink.
Extra dialogue concerning Sauron's buildup of forces, gathering of allies, plotting, etc.
Éomer finds his cousin Théodred mortally wounded and brings him to Edoras.
An extended scene of Gríma exiling Éomer.
An extended scene of the encounter between orcs and Uruk-hai traveling to Isengard.
Frodo, Sam, and Gollum taking a break in the Marshes.
The funeral of Théodred.
The encounter between Treebeard and the hobbits Merry and Pippin is extended. A scene in which Merry and Pippin stay drunk only to hear the powerful voice of the Ent, almost falling off Treebeard's body.
Merry and Pippin drink Ent Draught, which makes them grow taller.
Merry and Pippin are attacked by Old Man Willow and Treebeard saves them.
Gandalf and Aragorn talk about Frodo's fate on their way to Rohan.
Eowyn serves a plate of awful tasting stew to Aragorn, who reveals his age to her.
In a dream, Faramir sees the boat carrying the body of his brother Boromir. A flashback of Faramir and Boromir at Osgiliath helps explain their relationship with their father Denethor and the latter's unsympathetic and almost hostile attitude towards his younger son Faramir.
Denethor sending Boromir to Rivendell to find out about the Secret Council called by Elrond and (presumably) the One Ring.
Legolas and Gimli comparing their Uruk-Hai kill count after the Battle of Helm's Deep.
Flotsam and Jetsam, a new scene where Merry and Pippin find food and Longbottom Leaf in Isengard.
Extended Scene of Sam's Speech at Osgiliath.
Faramir shows the hobbits the way out of Osgiliath.
Fan End Credits
The Return of the King
Extended scenes of Sméagol strangling Déagol.
The final confrontation between Gandalf and Saruman at Isengard; Saruman's staff breaks and he is stabbed in the back by Gríma Wormtongue, who is shot with an arrow by Legolas; Saruman falls from Orthanc and is impaled in a war machine. His palantír falls on the water and is found by Pippin.
The drinking game between Legolas and Gimli
The fighting between Gandalf and the Witch-king of Angmar in Minas Tirith.
Extended scenes of the Battle of the Pelennor Fields
The march of Frodo and Sam with the orcs in Mordor.
A flashback of Faramir telling Denethor that he would never use the One Ring.
Aragorn seeing the fleet of Corsairs ships.
Faramir and Eowyn in the Houses of Healing
Merry offering his services to King Theoden
Aragorn using a palantír to reveal the sword Anduril to Sauron.
A non-canon scene of Aragorn, Legolas and Gimli barely escaping from an avalanche of skulls after negotiating an alliance with the Dead.
Faramir and Pippin having a passionate conversation in Minas Tirith.
Gollum and Frodo struggling on Mount Doom.
Sam threatening Gollum about Frodo on the secret stairs to Shelob's Lair.
The confrontation with the Mouth of Sauron at the Black Gate.
Fan End Credits
New song called "Bilbo's Song" added to the closing credits