My two favorite Edsger Dijkstra quotes:
… if 10 years from now, when you are doing something quick and dirty, you suddenly visualize that I am looking over your shoulders and say to yourself “Dijkstra would not have liked this”, well, that would be enough immortality for me. (From EWD1213.)
and:
Elegance is not a dispensable luxury but a quality that decides between success and failure. (From EWD1284.)