I'd like it if Linux became a highly-polished piece of OSS like Firefox. But I don't think that will happen, as an OS is far more complex than a browser. The OSS community can't even get an office suite or photoshop clone to be good, so I think an OS is definitely out of the question.
Still, I'd like to at least try SteamOS to see if Valve has the skills to backup their talk.
BSD is one of the most polished operating systems out there, it just doesn't have the support that windows has.
I'm hoping that SteamOS is highly polished and well maintained so that it's a good alternative to windows. I thought the goal of Ubuntu was to bring it to the masses by making it more accessible but last time I tried it, it seemed more trouble than it was worth, though 90% of my trouble was getting the graphics card to work properly.