Massive megaton incoming.
http://www.theverge.com/2012/3/2/2840932/exclusive-valve-steam-box-gaming-consoleAccording 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.
The consoles will also take advantage of Steam's "Big Picture" mode, a feature Valve touted last year at GDC, but has yet to release to the public.
According to sources, the Steam Box isn't intended to just clash with current gaming consoles. Rather, Valve wants to take Apple and its forthcoming new Apple TV products head-on. Newell has clear questions about Apple's strategy, telling the The Seattle Times "On the platform side, it's sort of ominous that the world seems to be moving away from open platforms," adding that "They build a shiny sparkling thing that attracts users and then they control people's access to those things."
The Steam Box could be unveiled at GDC, though we're also hearing that the company may wait until E3 this year to show off what it's been working on.
My money. Take all of it.