"From those to whom much is given, much is expected."

This speech (from Bill Gates to Harvard graduates last year) is flat-out amazing. It's long, and starts off very light-hearted, but is an extremely rewarding, high-impact read. I strongly recommend you read it;

http://www.gatesfoundation.org/MediaCenter/Speeches/Co-ChairSpeeches/BillgSpeeches/BGSpeechHarvard-070607.htm

(alternatively, you can also watch a video of the speech)