Xbox 2 and XNA Studio at GDC

Xbox 2 will have a multicore processor and be able to perform one trillion calculations per second. Not only that, you can use XNA Studio, built on Visual Studio Team System to develop games. Sweetness.

Quoted from the Microsoft press release

A well-balanced system that will deliver more than a teraflop of targeted computing performance

A multicore processor architecture co-developed with IBM Corp. that provides developer “headroom” and flexibility for the HD Era 

A custom-designed graphics processor co-developed with ATI Technologies Inc. designed for HD Era games and entertainment applications

XNA Studio
MS Press Release
Quoted from News.com

XNA Studio is one of the first major products to come out of the XNA Initiative Microsoft announced a year ago to standardize game development across different systems. Developers could use the same XNA tools to create games for Windows PCs, the current Xbox and future versions of the console, Microsoft promised.

XNA Studio is based on Visual Studio Team System, Microsoft's collection of code-writing tools for Windows developers who work in large teams.

XNA Studio will include similar collaboration features meant to facilitate the exchange of code between programmers, designers, quality assurance testers and other members of a development project, Microsoft said in a statement. The software will also introduce a new unified file format to ease sharing of game assets.