I know that I will be buying a second gaming system when I finally move back into my house. I have the XBOX 360 currently and that will have a permanent home in my home office (so I can finally play RB whenever I want).
As for the second console, that remains to be seen. I bought the XBOX specifically for RB3. Since it's purchase I have installed Portals2, Quarrel (Risk meets Scrabble), Risk Factions and downloaded several demos of games that I never got around to purchasing the full versions of.
It kind of goes without saying that the second console I get needs to support RB. With the WiiU being the only console of the next breed to supposedly do that, it might be the best contender for the living room location. Alternatively, I could purchase a second XBOX 360 or a playstation 3 for the living room. There are distinct advantages to both, which I assume everyone can already suss out for themselves. It's not going to be an easy decision at all. Even if my wife allowed me to get two additional consoles, it would still be a tough, if not tougher choice.
Going to have to just see where my research (studied the differences between PS3 and XBOX 360 for about a week before pulling the trigger on the XBOX) takes me.