With the removal of hardware accelerated Sound, and thus rendering our Sound cards useless, I have experienced quite a lot of annyoing side effects. Huge lag spikes, high latency crippled sound.
After reading the official World of Warcraft Technical Forum I found a a message, that old audigy 2 drivers would fix the issues. It took me quite some time to find a driver that worked for me, but I wanted to share the link for you. Now everything seems to work jsut fine. Download the driver SBA2_EAX4DRV_031031.exe here: Audigy 2 ZD Driver
Notice, that this is a work around and an old driver, thus it may cause some issues with other programs. At least it worked for me.
Update: Creative Labs is apparently in contact with Blizzard about the issues(Link):
I have an update for you on this:
Following the recent WoW patch and the ensuing forum debates concerning audio, Blizzard's director of audio took the time and trouble to contact our developer relations group to discuss the matter. He explained that the recent audio changes in the game were necessary, extensive and ongoing. Initial efforts to turn on hardware support with the new audio implementation were unsuccessful and they didn't have any time left to work on it prior to the patch release. However, he has assured us that once they have had the chance to clear up the immediate issues with in-game audio they will turn their attention back to enabling hardware audio to work again via the new scheme. Creative greatly appreciates the positive response that Blizzard has offered in answer to its concerns, and while there can be no guarantees, we are optimistic that Creative soundcard owners will once again be enjoying a fully immersive WoW experience complete with hardware based 3D mixing and effects in the not-too-distant future. In the meantime, please ensure you have the latest drivers loaded for your card to ensure best compatibility with the new audio system introduced in the recent patch. Thank you for your understanding.