In that page ATI states:
The future of 3D gaming on the Mac will be unveiled at the Macintosh Gaming Theater. Meet “Ruby,” ATI’s critically acclaimed Digital Superstar , introduced in 2004 in the animated demo “DoubleCross.” Ruby has recently reappeared in the fast-moving “Dangerous Curves” demo, and you’ll get a chance to get up-close-and-personal with her as she is running real-time on Mac OS X. Powered by the latest ATI graphics, you’ll see many techniques previously only seen in the latest Hollywood blockbusters. Join ATI’s 3D Application Research Group for an overview of the techniques developed for Ruby and a glimpse into the future of Mac gaming.
It sounds like ATI may be releasing new video cards and GPUs at Macworld. If so, it's quite possible they may be based on the PCI Express (PCIe) interface (not to be confused with PCI-X), since ATI's recent PC video cards are built around this interface. If any newly announced cards are indeed PCIe, then Apple will also have announced new Power Macs, since Apple's current Power Mac line does not support PCIe.