A great scene. Still, I wish they'd shown the boat being pushed out into the water by an invisible person and Sam realizing why. . . That's a great mental picture as well.
I have made comments before about parallels with the New Testament in LOTR, and this sequence is clearly one of them, it seems to me. We know Frodo thought that his duty would be done when he got the Ring to Rivendell. After the council he knew that he had more to do, but he was only one in the company of some of the Great Ones of his world. Then, after the stress of Moria and losing Gandalf, Galadriel tells him the bitter truth, that the entire weight of things is on his shoulders, that he cannot look to the Fellowship for help.
Then occurs the scene where Frodo says that he does not want to do what he has to do, and Gandalf tells him that we do not get to choose what circumstances we face, but only can choose how we will deal with them. I think that this is almost exactly equivalent to Christ's passion on Holy Thursday, when he asks the father to take away the cup which he is to drink, but finally says 'thy will be done'. Most of you reading this will see it on Holy Thursday, perhaps this dramatization of such a scene will help us all to contemplate just how bitter such a choice can be. But through Christ's choice we all may be saved, as Middle Earth was saved by Frodo's choice.