If I have the choice of an elf princess or a shield-maiden of Rohan who knows her way with a sword, I think I'm taking the shield-maiden. Aragorn must have some kind of ear fetish to choose Arwen.
Elrond is a jerk. He's a lot more kind in the book.
I don't care if it's not in the book: I get chills every time the elves arrive at Helm's Deep. Now THAT's an army.
Gimli still gets the best lines.
The added scene with Boromir, Faramir, and their father, Denethor, sheds some much-needed light on Faramir's motivation for taking the ring to Osgiliath. I still don't like the choice, but it makes more sense with the extra footage.
I don't know how it's possible, but the battle at Helm's Deep gets more dramatic each time I watch it. When Aragorn and Theoden ride out together against hopeless odds, and then Gandalf and Eomer appear with two thousand more riders... well, it's just better each time.
Overall, the new scenes provide clarification for choices and events in the original version. I liked everything that was restored, except for Theodred's funeral. The most moving scene in the theatrical version was Theoden's grief at his son's grave. The funeral scene just delays that emotional moment, and I preferred the original edit. But that's my only complaint. Like the extended edition of Fellowship before it, The Two Towers improves by leaps and bounds in this longer version. Peter Jackson HAS to get the Oscar for Return of the King.