8) Valve changes Xbox brand name to Steambox . . . . wait . . .

That would kill the console though. Nobody would buy a Sony console if there were no exclusives.

I'm not sure. Valve doesn't seem to be much about exclusive map packs/games/etc. So it's hard to imagine what they'd have for their own console's exclusives. You're definitely right on the trading cards, and you gotta get the inevitable Steambox hat in TF2 (while you get murdered by anyone using a mouse). I think they might just end up betting on the hope that there's enough demand for that sort of console. Demand for the device itself will always be a much bigger cause of sales over any sort of exclusives. Even if the Steambox sells horribly, the majority of the sales that do happen will be because someone wanted a Steambox, not so they can get some game exclusive to the console (temporarily for sure, if it's a big game).

But if they DO have an exclusive game, hm... Obviously Counter-Strike would be a no go as an exclusive since Valve respects that series' very dedicated mouse-loving crowd. I can't see them making a Team Fortress 3 for a very long time if at all (with the very successful hats system and still highly active online community), and that game's also strongest with a mouse. As mentioned before, Left 4 Dead and Half-Life are both too big to be exclusive. I think you know what I'm getting at: Alien Swarm 2 exclusive to the Steambox!!! Just kidding. Portal 3. If there is any big exclusive that's not new IP, it'll be that game. Anyone who adores Valve adores the Portal and Half-Life series above all else, so Portal 3 exclusive (temporarily) to the Steambox might be enough to convince them to buy one. Since Portal isn't about accuracy, a mouse isn't that important in playing it, so it's the perfect game out of all of Valve's big IPs to focus on for their controller-based platform.

I was just thinking about it, and you said they have to do something to entice the PC-users to get one. However, I think maybe they devised the idea of a Steambox so that they can dip into the console market and steal consumers from there. They already have the PC market in the palms of their beautiful, sausage-fingered hands, but they don't have much of any grasp on the people who use exclusively consoles for their gaming. I'm sure they'd love to get people who game mostly on the PC, but I don't think that's their primary target. People game on the PC because they like the highest def graphics, customization, and mice, among many other things. A Steambox loses all of that, for the most part (if it's going to be affordable for the average consumer). So I think our entire discussion is moot.