Last week I went to Phoenix with my friend AJ to see a presentation by Edward Tufte - if you have not seen Edward Tufte's work it is without a doubt worth a trip to his website. The price of the course includes four of his books and about six hours of presentation.
I really enjoyed the presentation! I have read various topics on his web site ('ask E.T. forum') and read part of Envisioning Information - with that background the best part was getting a broader overview of his ideas (which - in retrospect - I really missed in my previous reading) and a good framework for understanding the examples in his books. I also appreciated that E.T. was careful to give a number of interesting suggestions about ways to bring his ideas into the 'everyday' working world - useful information that was very much appreciated. Highly recommended!