According to "a high-level manager who asked to remain anonymous", around 80% of Microsoft employees own an Apple iPod. It shouldn't be suprising that well-paid, high-tech workers carry the popular audio player, but it is ironic. Apple and Microsoft are direct competitors and the Apple iPod is the most notable MP3 player that is not compatible with Microsoft's online music store technology PlaysForSure.
There is at least one notable exception to the iPods-at-Microsoft rule. Bill Gates carries a Creative Zen. [Via Engadget]