Cory Doctorow has a blog post up on Boing Boing entitled Mark Pilgrim's list of Ubuntu essentials for ex-Mac users where he writes

Mac guru and software developer Mark Pilgrim recently switched to Ubuntu Linux after becoming fed up with proprietary Mac file-formats and the increasing use of DRM technologies in the MacOS. I've been a Mac user since 1984, and have a Mac tattooed on my right bicep. I've probably personally owned 50 Macs, and I've purchased several hundred while working as an IT manager over the years. I'm about to make the same switch, for much the same reasons.

You could probably write an entire Ph.D dissertation on what would motivate someone to tattoo a corporate logo on their arm. Maybe I should buy a Mac just so I can figure out what all the hype is about.