Traditional design may be better for health, but it destroys collaboration. IMHO the best office design I've ever been in were simple team rooms - everyone on a team (or sub-team) would work in a large office that they can tailor the way they like (lighting, decor, etc). This really helped build team cohesion, and since everyone is just a shout away it broke down the walls preventing collaboration.
And I suppose it has the added benefit of only getting one team sick at a time :)
It really depends on the type of work you're doing. For jobs that require a lot of collaboration, open areas holding around 10 people can be good. Some jobs would benefit more from having offices that hold 2-3 people each, and for jobs that require you to be on the phone a lot (sales, marketing, support, etc.) private offices really are a better option.
And I suppose it has the added benefit of only getting one team sick at a time :)