Bartlett's Familiar Quotations is a great place to explore "sound bites" from great literature. I find them useful for lectures, papers and t to explore some interesting nooks and crannies of great literature by taking the quote and then "reading around it" to get the context. In fact John Bartlett had a great quote about his quotes, "I have gathered a posie of other men's flowers, and nothing but the thread that binds them is my own."
Several weeks ago (by way of doggdot, I think) I discovered Damath Rajapakse's collection of Software Engineering quotes and had a great time sampling the quotations. Dr. Rajapakse has done a great service for software engineering students and lecturers alike. It is a highly recommended site to visit and bookmark, especially for folks interested in software engineering. Enjoy it and thanks to Dr. Rajapakse for creating such an entertaining and useful compilation.