If this report is true, then Microsoft has set up a serious "Steal their Thunder" moment for the PS3 launch:

Capitalizing on the blockbuster FPS from Bungie, Microsoft is planning its third edition in the epic series as a full-fledged next-gen title, to be released in time to compete with the release of the rival PlayStation 3 system -- day and date, Sony will be facing with its new system the release of one of the most anticipated games of the next-gen system wars. Further info is being kept secret by Microsoft and developer Bungie.