For me there is absolutely no argument. I am now on my 4th Mac and I wouldn't have anything else. I have had this one about two years now and have had absolutely no problems.
As already mentioned, all these extra bits and pieces you can get for PCs but not for Macs just aren't necessary anyway on a Mac.
I'm on OS X and I can automatically open most documents from PCs and if not there are usually ways round it.
I have to use a PC for a voluntary job I do and I hate it - it really doesn't compare with my Mac even though it is a new sooper dooper wireless lap top.