I love mine. 3 years this month I have owned my Mac, never had a single problem. The argument about not being able to run PC programs is now void because you can split your hard drive to run PC programs, and Microsoft programs now run seamlessly between the two.
If you are concerned about running Windows programs simply be sure to buy the Mac-capable Windows programs either that or do as suggested and split the machine into a Mac and PC. Allows you to simply click from one operating system to the other with no effort and in the same screen.
Also far less concern with nasty viruses...viri?...nasty bugs.
Being a teacher, we use Macs at school. I will tell you that I have a 4 year old Powerbook that still runs great. I do the updates when they come out and it runs just as good as my 2 year old Dell PC. I wouldn't mind having one of the newer machines that runs both Mac and Windows (as long as its not Vista!) What's weird is that, at home, I've always run a Windows based machine. I don't know why. Honestly, I think the Macs are better and now that they are completely Windows compatable, I can see my next home computer being a Mac.