There is an interview with J. Allard at IGN Xbox. HBO was the first to post about this. Allard is the general manager of the project, and so would be in a position of authority to speak on its development. Here's a Halo-related snippet:

IGN Xbox: What are your thoughts regarding what makes a launch important, and what make a launch successful?

JA: The launch is such a complicated thing. There's so many variables in the equation, but the most important parts of a launch are two things: one, great content, and two, great content. Well, and three, quality of the experience. But fundamentally, you need the best games. So from our point of view, the launch portfolio that we're putting together, with all the great partners in the industry, is going to be world class. First impressions are very staying, and we're going to have a great launch lineup. Not only do have to deliver great games, but we have to deliver an experience where you pop it in, it works, and the game not only satisfies the creative demands of the console players, but the quality demands. We have to do a lot of supporting things, but that's secondary to the games. If we don’t have great games, we lose.

Among other things, the interview delves into the proposed hardware setup for the X-Box. Allard confirms that broadband Internet and multi-box LAN play are both important parts of their multiplayer strategy, but also denies that keyboards and mice are being considered as a means to interface with the machine. Also, it seems somewhat apparent to me now that Bungie must have first shown an interest in the X-Box as a development platform after it was officially announced at the Game Developer's Conference in March.