Windows and Linux at work ; OS X at home ; iOS on my iPhone, iPad, and new Apple TV; and whatever iPod Nanos run .
If you get into versions, it's XP for all the Windows work; Redhat 4, 5, and 6 for Linux at work; currently straight Debian (I think Sid?) at for Linux at home; mostly Leopard through Lion for OS X ; and iOS 5.
Oh, and I have a dev edition of an Intel tablet I got for free that I've booted exactly once. I think it runs Maemo or Meego or something?
Do we count firmware? I'm pretty sure my receiver, TV, Blu-ray player, and cameras all run things sophisticated enough to be called OSs....
 And very occasionally Solaris (8, mostly, I think).
 With occasional interludes of Windows or Linux at home, mostly via VMs.
 Also miscellaneous earlier iPods, from original up to 3rd gen Shuffle, that get used an average of once a year.
 And one ancient Tiger box I boot maybe once a year.