There's been persistent rumors about Valve working on a "Steam Box" gaming console and while it has been denied by the company, consider the rumor revived as Valve has just explicitly stated that it is and will be "jumping" into the computer hardware space.
According to a job listing for the "Industrial Designer" on Valve's website, it states that although the company is traditionally a software one, it is frustrated by the lack of innovation in the computer hardware space.
Valve is traditionally a software company. Open platforms like the PC and Mac are important to us, as they enable us and our partners to have a robust and direct relationship with customers. We’re frustrated by the lack of innovation in the computer hardware space though, so we’re jumping in. Even basic input, the keyboard and mouse, haven’t really changed in any meaningful way over the years. There’s a real void in the marketplace, and opportunities to create compelling user experiences are being overlooked.
Valve hasn't confirmed what specific kind of hardware it will make, so whether it'll be some form of a computer or console, nobody knows yet. However, PC and console makers be warned, we have a new kid in town.