Results: 88 responses for Windows (76%) (38 for XP, 28 for 2K, 22 for others (NT, '95, '98)) 27 responses for Mac OS (24%) (18 for OS X, 9 for others) Many people were running multiples, each was counted. Also a few folks running Unix/Linux/Solaris. NOTE: Purpose was to satisfy curiosity, not start a "my OS is better than your OS" war. Thanks a lot to all who responded!