There has been an ongoing debate as to when Vista might be released. As with all large complex software development processes until you finally release it into duplication you are never certain.
Several of the comments re slippage, and why not before Christmas, and what OEM's want etc have in some instances missed the point.
Microsoft has customers that build to two different types of manufacturing models.
Dell builds to order, HP for instance and most of the other companies build to stock. So in light of all sorts of legal ramifications and also marketing problems, a release that would give Dell an edge due to it quicker time impliment in production, would cause all sorts of problems in customer relations.
With VISTA going to more widespread beta this week, it will still be touch and go to see if they can make the release to duplication in November
Here is an interesting interview with Jim Allchin
http://news.com.com/Allchin+Still+worried+about+Vista/2008-1016_3-6076266.html
Sharyn