Well, I didn't see this coming, to be perfectly honest.
From the article:
What makes this decision so remarkable is the fact that Paramount was a fence straddler: the company has issued movies in both HD DVD and Blu-ray over the past several months, choosing to evaluate the market. Paramount says that its evaluation uncovered two benefits to HD DVD. First, the format is less expensive to produce, as we have touched on before. Second, Paramount described HD DVD as being superior owing to "market-ready technology."
Speilberg's movies are an exception, and could come out on either or both formats.
Just when I thought things had stopped getting interesting...