You should definitely go. I've seriously thought of going again (because once you've attended the two-day seminar you can audit it again for only $295 -- although I'd also have to pay for travel and hotel). Probably won't get to go this year, though.
NOTE: I previously said the GTD seminar was free to audit. It's not (my mistake -- don't know why I thought that), but the $295 rate is a great rate in any event. I still plan to go back for a re-up on the two-day seminar at some point. I keep listening to the CD version, and everytime through discover something I hadn't seen before.
I just wanted to post a correction. The audit rate is $295 for our Getting Things Done seminar. You can contact me directly to register at this rate. I can be reached at Jodi@davidco.com. Just let me know which seminar you attended in the past.