In the ECC (Engineering Computing Center) all the machines on the Linux side of the lab run Firefox. On the Windows side they run both, (I think) but all the Windows machines are so locked down that you can't even right-click anything. (Seriously, they've disabled right-click context menus because of the possible security holes they open up)
And yes, it's literally "sides" of the lab. The two western rooms are full of Windows machines, the two eastern rooms are full of Fedora Core machines. East side hardly ever fills up either, which is good for me when I want to get online. I am losing faith in the next generation of engineers though.