John Carmack’s GDC2K4 keynote speech, transcribed and published by Eurogamer in three parts:
http://www.eurogamer.net/article.php?article_id=55089
http://www.eurogamer.net/article.php?article_id=55107
http://www.eurogamer.net/article.php?article_id=55119
Well worth reading if you’ve got a spare half-hour.