I look at a computer screen for a large portion of the day. When I am home, and need/want to look at a computer screen, I’ll pay extra (and do) to look at one that, out of the box, just looks better than the alternative.
(Before windows7 which I haven’t tried yet) OSX simply looked better (to my eyes) than XP. Everything; the fonts, the graphics, websites, the windows, etc. It is pretty simple, if given a pretty thing to look at or a not-so-pretty thing to look at, I’ll choose the pretty thing assuming the consequences aren’t too high for doing so (price, performance, whatever). For me, the downsides to the Mac (price and games) don’t outweigh this. For others, it will…
Heck we’re born with a preference to want to look at the attractive over the less-attractive: link