Hmm. Mac VS Windows War.
I don't see much of a problem using both. I used Windows, I was fine. I used Mac, I was fine too. I used Linux (Ubuntu), I had some problems, but fine too.
It's the user's preference. And I disagree to the "finding replacement programs".
It can be quite tough. Yes, you will find a alternative, but the question is, how good is it compared to the orginal Windows app.
I still feel the Windows Live Messenger is better than all the Mac alternatives, although Adium comes close, but I ran into some problems.
The Microsoft Messenger for Mac was not on par with the Windows version either. aMSN is :nono:
Another app would be Picasa which I love so much. You might say, "I have iPhoto for Mac!" But iPhoto uses so much space that I decided not to use it. I tries to take control of your photo files? Hmm. I prefer Picasa.
And if you have Windows and Mac on your home network, sharing printers might be a problem. You gotta take time to figure out.
Maybe in the future, this will change?

Mac is a little overpriced too. ;p
I never had run into much problems with Windows. It only depends on how well you manage it and not screw it up. No viruses for years now, and speed is fine enough. A format helps once in a while though, which is troublesome. LOL.