Some of the best commencement speeches with their notable quotes can be found at graduationwisdom.com. The co-ordinates for the best 2013 speeches are: http://www.graduationwisdom.com/speeches/best-commencement-graduation-speeches-with-inspirational-quotes-2013.htm
That page also links to the best speeches of other years.
A 2012 speech that attracted much attention was given at the University of California Annenberg by Maria Shriver of the Kennedy clan and former First Lady of California through her marriage to Arnold Schwarzenegger. The speech was entitled The Power of the Pause and urged students to change the state of our communication, which she believes is out of control.
An excerpt: "Change it from criticism and fault-finding to understanding and compassion. Change it from nay-saying and name-calling to acceptance and appreciation. Change it from dissembling and dishonesty to openness and explanation. Change from screaming to speaking."
The full speech can be found at Shriver's website: