A while back, Peter Gutmann published a report discussing content protection under Vista; that report has led to some discussion in the blogosphere about Blu-ray playback. I wanted to take a few minutes to clarify some things.

Much of the discussion has related to Vista's content protection methods, including HDCP. Much of the information currently floating around the blogosphere is outdated, especially that related to Blu-ray playback and HDCP.

Most of the commercial content for Blu-ray (and HD-DVD for that matter) has protection policies that must be enforced by the playback device. Previous versions of Windows have contained similar content protection policies that have not adversely affected the use of the Windows platform as an excellent playback method, including Macrovision ACP on standard definition playback, Certified Output Protection Protocol (COPP) and S/PDIF.  None of these methods, including HDCP have made the windows platform a less reliable playback vehicle. Further, these requirements are the same on most commercial and consumer electronics devices that offer playback functionality. Dell systems provide a robust playback vehicle. Prior to offering Blu-ray for sale on any system, Dell validates the configuration for great playback on Vista. 

Currently, with the exception of the XPS One, all Dell systems with Vista will playback Blu-ray correctly with any HDCP 1080p-capable monitor. The only exceptions are the XPS One (as Lionel pointed out) and configurations with the some entry-level versions of ATI cards which will have HDCP content protection but will not have the memory bandwidth to play back in full 1080p.  For additional information on Blu-ray playback in full 1080p with HDCP, please see this entry on the Microsoft Vista blog.