Here are my thoughts as both teacher and student:
Proscenium: As a student, I've found these to be dull, for many of the reasons given. You really can't see or hear the teacher well; if there's anything that she's trying to teach, it's extremely difficult to follow. As a teacher, trying to get students to follow what I'm doing in the front of the room is challenging, if not impossible. I can go to the back of the room, but students who are bent on websurfing tend to track my movement around the room, in order to open a new, work-related, window when they think I can see them. (Strangely, however, they're never as good at this as they think they are...
However, whether as a teacher or a student, I do find these rooms challenging in terms of simple navigation. Getting to an individual terminal requires the interruption of several people. Also, as a larger woman, it makes me feel extremely self-conscious, as my chances of getting through a row without bumping someone are minimized. In the majority of these classrooms that I've been in, the desks have been in a fixed position, so there has been no way to remedy this, either for my own comfort or that of others.
Perimeter: I haven't taught in a perimeter-style classroom, but I have been a student in one. I felt extremely isolated from other students; group work with anyone not sitting right next to you is difficult at best in this layout. Also, even as a very confident writer and computer user, I felt extremely exposed to the instructor, as she could walk up behind me at any time. It might be odd, but this really took away from my experience.
Pods: I've seen them, but never worked in them. I'd like to, though, as I think they'd handle a lot of the issues I've seen in other classrooms.
This brings me to the other layout...the godsawful one of our classroom in Hayes. In some ways, it's like the worst of both worlds. We have all the isolation of perimeter, with all of the difficulty of teaching and group work you get with proscenium. Also, if the printer is operating, it's all but impossible for anyone at the instructor's station to hear comments from the back of the room.
I don't know if I'll be designing the layout of a computer classroom anytime soon, but if nothing else, I'm glad that this week's reading gave me the chance to articulate why ours pisses me off. :)