As recommended by Cyberlink, you will need NVIDIA ForceWare drivers later than version 93.71 and ATI Catalyst drivers later than version 6.7 in order to ensure compatibility with PowerDVD Ultra for Blu-ray or HD DVD playback. It is worth keeping an eye on this thread @ AVS Forum, since there are certain combinations of drivers that will work best with PowerDVD Ultra. But the general rule is to get the latest drivers, which will work better with PowerDVD Ultra or WinDVD.
When this guide was first wrote, there was really only one commercially available product to playback Blu-ray and HD DVD movies, PowerDVD Ultra. Since then, several alternatives have popped up, including PowerDVD's main competitor, WinDVD. WinDVD 9 Plus Blu-ray adds both Blu-ray and HD DVD playback, and rivals PowerDVD Ultra in terms of support (both now support Blu-ray Profile 1.1).
There has also been some favourable views on Arcsoft Totalmedia Theatre, which also supports both Blu-ray and HD DVD playback, and it comes with a 15 day trial version so you can test it out for yourself!
So that's it for now. More information will be added to the guide as it becomes available. While Blu-ray and HD DVD playback should already be possible for some people, hopefully Blu-ray and HD DVD playback will become less simple as better hardware and more software become available.
Got more questions? Post them in our High Definition DVD Forum and get them answered by other expert users.