When we were preparing our apartment for Bacon we had to figure out how to block off the six-foot-wide doorways in our apartment because the usual baby gate solution just wasn't wide enough. We found the Precision Pet Pen and it has proved to be one of the most useful puppy purchases yet...
The Precision Pet Pen is made up of eight 2' wide panels and can be configured in a number of different ways, including a 16' fence or up to a 5' circle. We use it to as a fence to divide the living room from the rest of the house when we are at home and, since Bacon is still a puppy and not trustworthy yet, we make a large pen in the living room when we leave him home alone. He seems to like this best because it is open play space and big enough for his crate (bed), too. And he gets to stay in the same place which makes it his place—very important for little pups.
We would say it's near perfect but it is fairly heavy when we need to move it and the metal feet have done a number on the finish of our hardwood floors. We are thinking of something to put on the bottom so it doesn't scratch but we haven't found a solution that will stay put and is puppy proof. Overall, we would highly recommend it for people living with large, open floor plans that are hard to divide off to keep your puppy out of trouble.
No Bacons were harmed in the making of this post—he was in his pen while we painted our foyer to keep his white coat paint-free.