Dennis Bishop, the Director of Information & Technology at the University of Oregon School of Law, has in the past been good enough to send me a breakdown of laptop use at his school. Now he has updated numbers for Fall 2010. Macs are doing rather well:
Student Platforms (all)
MacOS = 371 (67%)
Windows = 166 (32%)
Unknown = 5 (1%)
Faculty/Staff Platforms (all)
MacOS = 70 (77%)
Windows = 21 (23%)