@amigadave
interesting poll. for at least three hours in a given week, i use the following:
1. amigaOS 4.1u3
2. solaris 11
3. GNU/linux (openSUSE 12.1rc1)
4. AIX 7L
5. z/OS v1.13
6. z/VM v6.1
i use amigaOS and solaris at home; the others are for work. i haven't used windows in years, er, well, except when i have to recover data or fix some odd configuration problem on my wife's PC. i try to get her to go over to something more sane, but....
edit: if you're also interested in mobile platforms, i'm running blackberry OS 5.x on my mobile and blackberry tablet OS 1.0.7 (which is QNX-based) on my playbook....-- eliyahu