The good conferences I attend (as a participant/delegate) always seem to have more good session than I can possibly attend. I find the presentation material to get a flavour of other sessions, but it is always better to see the session in person. There are a few sessions I have noticed in the schedule that sound like they will be very interesting.
Walker Royce is a must-see speaker (which is why we asked him to deliver a keynote this year). He always seems to make potentially complex topics clear and understandable, and cuts right the heart of the topic. No waffle from Walker!
I am also looking forward to the systems keynote from Jaguar-LandRover. Should be a great talk from a very senior representative of JLR.
Look out for the Goldfish bowls. This format, that I first say at the excellent SPA conferences run by a British Computer Society specialist group, is a way to really engage in a session.