Thought I'd get this going again, though a lot of quotes might be taken up.
However, this one wasn't used:
"Once there was a boy called Eustace Clarence Scrubb, and he almost deserved it." VDT
I'm afraid I don't have a copy of SC at the moment, so this might not be quite right, but:
"Many have come to the pale beaches, and few-
"few return to the sunlit lands, you needn't say it again. You are a chap of one idea aren't you?"
Puddleglum, SC
"Welcome in the Lion's name. Come further up and further in." Reepicheep, LB I absolutely love this quote because it signifies the meeting again of one of the greatest characters of Narnia.
Another quote, which I cannot remember perfectly, forgive me, is Reepicheep's lecture to Caspian in VDT about his duty as king of Narnia and how he cannot go wherever he pleases if it breaks faith with his subjects.