Another tip of the [proverbial] hat to Curtis for this one.
I'm not sure why people are surprised that Michael Dell is running a Linux box. Dell is in a spot of a slump and their prospective clients are clamoring for Linux on Dell's products. So he's bound to be checking things out. Any good CEO would, and he is surely that.
I hope Ubuntu is one of the distributions Dell chooses, if indeed they advance past selling "Linux compatible" machines and actually choose one or more flavors of Linux. And for those of you who are not inclined toward Ubuntu, don't worry. You'll be guaranteed the hardware for your favorite distro to use.