It's a longstanding rivalry. Mac people are seen as cultish and creative and more likely to be city dwellers, while PC users are thrifty, practical down-home folks. Whichever way you skew, your identification with one tribe or the other is likely a strong one. Leaving aside the Linux geeks for the moment, you're more like to use one or the other than to use both. Hunch, a site which collects all kinds of interesting data about its users dug even deeper, discovering that, not only do the stereotypes hold, but they extend to political affiliation, choice of news outlet, and even food picks.