My first reaction was that this was a bit over the top, but... on reflection, not really. Fog Creek's setup looks nice, but outside of that, I've rarely seen any company treat their developers like they treat their marketing folks, legal, financial and other areas. Financial/accountants aren't generally expected to sit in an open room with 15 other people with foosball games going on in their line of site.
Should we encourage "pair accounting" and have accountants share a laptop screen to get their work done?
There's an element of mentoring and support that can go on in those open environments - adhoc help, etc - but that seems to be partially a cover for the fact that many people aren't all that good at what they do, and the better people need to help train (sorry, "lead") the less experienced folk.
My own experience in open plans, beyond the general noise, is that it's harder for people to admit they have a question, because it's visible to an entire group. Likewise, it's harder to call someone out for not pulling their weight in an open plan setting, without calling more attention to the interaction.
"private by default" seems to work well for OO developers, just not when it comes to their office space.