According to a recent article published by The Verge a new gaming system that plays steams pc games could be in the pipeline.
According to sources, the company has been working on a hardware spec and associated software which would make up the backbone of a "Steam Box." The actual devices may be made by a variety of partners, and the software would be readily available to any company that wants to get in the game.
Valve have recently filed for a patent on a controller design with interchangeable peripherals, meaning that it can be reconfigured depending on the type of game you're playing. Adding fuel to that fire is a rumor that the Alienware X51 may have been designed with an early spec of the system in mind, and will be retroactively upgradable to the software.
Steam also announced at last years GDC that they were looking to bring in The big picture and according to the company's press release in 2011 "With big picture mode, gaming opportunities for Steam partners and customers become possible via PCs and Macs on any TV or computer display in the house."
The steam box could be announced by valve at GDC, but they could leave it until this years E3.