If you are looking for text that is good for an undergraduate course in differential geometry, I would suggest Differential Geometry of Curves and Surfaces by Banchoff and Lovett. See http://www.amazon.com/Differential-Geometry-Curves-Surfaces-Banchoff/dp/1568814569/ref=sr_1_3?ie=UTF8&qid=1317835776&sr=8-3 . It was published in 2010 so did not show up on this earlier.
The book comes with online computer graphics that help develop an intuition for the topics in the book.
