We got an email from Valve! It says: "We have three announcements to make beginning with the first one on Monday morning." What are they about? Well they're about "the steps we're taking to make Steam more accessible on televisions and in the living room."
So probably a Linux-based Steam box, then. The three announcements are going to appear here. How exciting. Well, it would be if I could ever claim the living room back from family members. Sigh. Don't worry, desktop, I'll never (be able to) leave you.