Toshiba - There has been a war raging internally as to how much more money they are going to continue blowing through in a futile battle. That was before Warner decided to dump HD-DVD. Toshiba is the only manufacturer of HD-DVD players and will almost certainly halt production soon to stop the bleeding.
Microsoft - Will now be free to give up pretending their ever cared about HD-DVD and move on to fully promoting their download service
Xbox fans - Will now start flooding gaming and digital media sites with Microsoft download vs. BluRay articles and posts
Universal - Has a major HD-DVD backer running things who will most likely soon be making the standard 'decided to spend more time with my family' exec exit line and then fully embrace BluRay sometime this year
Paramount/Dreamworks - The only real question as to what will happen. As of right now they are contractually stuck to a dead movie format for the rest of the year.
New Line - Owned by Warner and will be BluRay exclusive shortly along with Warner. So Lord of the Rings and the rest are on the way.
Studios will now start taking full advantage of the larger BluRay discs with higher bitrate encodes now that HD-DVD is out of the picture.