(moved from stackoverflow)

I have found lot of discussions here on about which keyboard, desk, light or colored background is best - but I can't find one addressing the layout of the whole office.

We are a company with about 20 employees moving to a new place, something larger. There are two main development practices going on here with regular combination, the back end people often needing to work with the mobile people to arrange web services. There are about twice as many back end people as mobile people. About half of the back end developers are working on-site at any time and while they are almost never all in the office at once at least 5-10 spaces need to be provided - so most of the time the two groups are about equal.

We have the chance to arrange desks, partitions and possibly even walls to make the space good. There won't be cash for dot-com frills like catering or massages but now's the time to be planning to avoid ending up with a bunch of desks in a long line.

Joel on Software's Bionic Office is an article I've remembered from way back and it has some good ideas but I* (and more importantly the company's owners) are not completely sold on the privacy idea in an environment where we are supposed to be collaborating. This is another great link - The Ultimate Software Development Office Layout - I hadn't even remembered enclosed meeting rooms until reading this.

Does the private office stand in the way of agile development? Is the scrum enough forced contact and if you need to bug someone you should need to get up and knock on their door?

What design layouts can you point to and why would you recommend them?

*I'm not against closed offices at all but would be happy if some other solution can do just as well. If it can't... well, that's what this question is all about.