We don't really pack people in or use laptops, we have clusters of 4 or 6 desks that form larger rectangles and which are then stacked back-to-back, so you can easily talk with the people next to/across from you in the desk cluster or you can easily turn around and talk with the people at the next cluster. We generally organize each sub-team as 2 or 3 clusters of desks, with 4-6 developers sitting back-to-back and QA and PM on the opposite sides of the cluster. It makes pair-programming much easier, since all the developer's chairs are in the same open area, so you can easily pair with someone to the side or that sits behind you.
My current part of the floor has maybe 35 people in it, and there's kind of four sides of a rectangle to the building, so overall there are about 140 people or so on the floor. Generally, the clusters are spread out enough that you can't hear conversations that are happening more than about 20 feet away anyway, so the primary conversations you'll overhear are from other people on your sub-team, which are exactly the conversations you really want to be overhearing anyway. It really helps to keep everyone on the team in the loop about what's going on.
We have offices around the perimeter of the building that are unused so that people can grab them to have impromptu whiteboard discussions or make phone calls, which also keeps the general noise level down.
My current part of the floor has maybe 35 people in it, and there's kind of four sides of a rectangle to the building, so overall there are about 140 people or so on the floor. Generally, the clusters are spread out enough that you can't hear conversations that are happening more than about 20 feet away anyway, so the primary conversations you'll overhear are from other people on your sub-team, which are exactly the conversations you really want to be overhearing anyway. It really helps to keep everyone on the team in the loop about what's going on.
We have offices around the perimeter of the building that are unused so that people can grab them to have impromptu whiteboard discussions or make phone calls, which also keeps the general noise level down.