Registered thus far (Wiki-based registration) are just 28 attendees and six of those aren't yet confirmed. The XDS 2008 program right now just lists talks on the X.Org Foundation status, a future releases session, and an input summary on Multi-Pointer X and other improvements. Over the course of the three days though is room for 21 talks.
In comparison, last year at XDS 2007 were 50 attendees (their maximum capacity allowed) and even a waiting list had formed. The conference last year was three days long as well and was booked with talks, it's also where AMD had launched their open-source strategy. Hopefully we will see a last minute surge for XDS 2008...
The usual X.Org leaders will be there such as Daniel Stone and Keith Packard along with other Intel X developers (Eric Anholt, Ian Romanick, Gordon Jin, Jesse Barnes, etc). Planned for representing the ATI/AMD side is just Alex Deucher and hopefully John Bridgman. There from Novell's xf86-video-radeonhd crew is Luc Verhaegen and Egbert Eich. No NVIDIA engineers are scheduled to be there whether it be from NVIDIA Corporation or the open-source Nouveau group.
Keith Whitwell with Tungsten Graphics will be there as well, who lately has been working on Gallium 3D. Sun's Alan Coopersmith will also be there as well as Peter Hutterer, the mastermind of Multi-Pointer X.
We will be covering the three-day affair, which will hopefully end with several interesting talks. We also have permission to record audio/video of these talks, so expect those recordings as well.
For more information on XDS 2008 or for the free registration, visit the X.Org Wiki.