Certainly sometimes I want to go away and think by myself. I want that option, but not as the default.
If programmers don't work well together, then by Conway's Law neither will their code. Beyond that, batting ideas around is just more fun than playing the solitary genius - and produces more satisfying results.
The kind of open office I like, though, is one in which the people are all working on the same system. I agree that noise and interference from unrelated activity is a disaster. It's very simple: everything should be organized around the team.