While I would love to engage in the long-standing Mac vs. Windows war (my opinions are in fact heated), I will constrain my topic to my experiences as a user of both platforms with fair judgement and an avoidance of controversy (no name-calling in other words).
First I confess to a unquestionable fondness for the Mac. Having said that, it should not be taken as a challenge or a bias; the simple fact of the matter is that my first computer was a Mac and until very recently my only experience with Windows was checking my email at internet cafes and surfing the net at my Dad's house. However, I had the recent good fortune of a receiving an XP generation Windows laptop from a friend with computers coming out of his kazoo who thought I might put it to good use. And I have, too, and use it almost every day.
To be honest though, while navigation is not so hard to figure out within the filesystem, configuration can be very odd and roundabout indeed. The operating system also seems to be full of features that were slapped together and patched in at the last moment. One gets the feeling when working in XP that it is a 'work in progress' rather than a polished and thoughtfully designed system.
Now lest anyone accuse me of Windows bashing, I haste to add that I really know very little about the OS and a big part of my problems (which really aren't that many) come simply from not knowing where things are. I'm also working with a used computer which no doubt explains its quirky bugs.
I'm sure I'll always prefer Mac over Windows but that doesn't mean I'm a Windows basher. I quite like my Panasonic CF and it has served me well.