I'm an IT student and a consultant at the computer help desk at a well-known Institute in Troy, NY. We have a program where incoming students are offered a package including a Windows laptop, but we also explicitly support Mac OS X and Red Hat Enterprise Linux. The Help Desk will gladly give you an install image of Windows XP, Vista, or 7, but we also have discs for the major Linux distributions on hand.
Our wireless network is an 802.1x PEAP. Unfortunately, it doesn't self-identify properly so you must tell Mac OS X, Windows XP, and some Linuxes that it is a PEAP. There is an Android app to facilitate using our network. Out VPN is Cisco AnyConnect which is (surprisingly) cross-platform and exceptionally easy to set up.
Public computers run Windows, but there are a few Sun workstations running Solaris. Students have SSH access to a variety of public RHEL, AIX, and SGI machines. The CS department additionally provides access to some more FreeBSD, IRIX, and Solaris servers. By the time you are in Data Structures (Computer Science 2), everything must compile in GCC 4.current. People still using MS Visual Studio are quietly ridiculed.
Perhaps we are an exception from the normal experiences...