A lot of the ones mentioned definitely make my list - but I have a few more as well.
"Nothing ended, nothing begun, nothing resolved." - I think that line just speaks volumes about their relationship at the end. I wish they could have begun and resolved things but it wasn't meant to be. Painful.
The other is one from my signature. I'd include the entire passage but it's rather long - I will however give a little more text.
"... and still they clenched, pressing chest and groin and thigh and leg toghether, treading on each other's toes until they pulled apart to breathe and Ennis, not big on endearments, said what he said to his horses and daughters, little darlin." I can just see Ennis whispering this to Jack ... I'm kind of disappointed they didn't include this in the movie, but I also see why they did not. It just wouldn't have fit. Still, it's one of my favorite parts of the book.