It appears that anyone with a Creative SoundBlaster X-Fi or Audigy series of soundcards will have to wait until March 2007 before full non-beta drivers are released according to a member of their staff at the official Creative forum:

Due to additional requirements in the Windows Vista driver certification process, the release of the final signed drivers for the Sound Blaster range will move out beyond our initial projected date until early March. The current Beta drivers are still valid for use under Vista and are required to take advantage of the benefits of Creative ALchemy with the Sound Blaster X-Fi range to restore multichannel audio and EAX to your games. We appreciate your understanding for this change to the schedule as we work to bring you the best experience for your Sound Blaster series cards while adhering to the requirements of this new operating system.

This is a bit of a pain, but it is only a month away and it is very likely that updated beta drivers will be released before that date.