No, really: why? Why buy a machine with a Linux OS? Before you mount your Torvalds horse, think about it: what in the world does Linux offer? Lower price? Hardly. This article shows exactly what $200 *doesn't* buy. Stability? Again, hardly. Linux machines crash, oh, just about as often as XP or Vista machines do; oh, and over-priced Apples machines, too. Ease of use? Get real.
Again: why Linux? No knee-jerk responses. Think and write clearly. What does Linux offer that Windows/Mac OSs don't?