I can't speak for the differences of software or ability to things on one platform or another. I can say that we have an eMac, a PowerBook G4, and a dual 1.8 G5. I have been virus and problem free since May of 2002. I had problems with all PCs I have owned. Some were user mistakes, some hardware. All in all, it was stressful keeping up with all of the viruses and security holes in Windows and Internet Explorer.
I have found the folks at my local Apple Store (Albany, NY) to be light years ahead of the slackers that work at CompUSA, BestBuy, and Circuit City.
I have gone Mac and will no go back!