[Beanamir of Gondor]

To tell the truth, the Aragorn-Arwen scenes positively bored me in TTT. For one, I rather enjoyed the patient, platonic, no-touchee relationship between those two characters in the book; for another, the characterization in those scenes felt a little flat to me, and didn't add much plotwise. I realize that they were most likely added in the hopes of keeping battle-bored viewers interested, but still...
I feel that PJ could have left the Aragorn-Arwen action out of TTT, added some stuff from RotK!Movie that was actually in TTT!Book (Flotsam & Jetsam, maybe even Shelob), and then had more room in RotK!Movie for The Scouring of the Shire and suchlike. And the movie probably wouldn't have suffered a bit.
I really have nothing to complain about as far as the A-A scenes in FotR and RotK go, however. They did bring Arwen down from the height of "Lady Arwen" to a more moderate stance of "Aragorn's girlfriend" or "Elrond's daughter", but that was fairly harmless, and, I suppose, made the relationship between grubby old Strider and lovely Evenstar a little more realistic for modern audiences.