My main machines at home and work are Debian installs, my home install is probably 8 years old now and has been transplanted across several machines. Since sid is a rolling release I just update it a few times a week and I'm always current. The work machine is a Mac Pro, it has OS X on it as well but I have no idea what version since I haven't booted it since I got the thing. I really just needed it in order to install rEFIt and get Debian installed. =)
Ironically and sadly, I'm posting this from my Win7 notebook that I have for work.