Get a PC if $ is an object as the Mac is around 3-5 times as expensive. Now as far as ease of use and not having to worry as much about viruses then go for the Mac. I just have an issue paying the kind of money they want for a machine that is outdated before you even get it out of the box.
I would personally use a Mac. Its much better than a PC. Apart from obvious technical reasons, which includes running Windows on it, its also a style statement. Its like on the higher end, in computing!
Being a consultant that uses a Mac and PC's (several because sometimes they don't work) you would be an idiot not to get a Mac. They are vastly superior in many ways and you can run windows on it if need be.
MAC! I adore everything Apple, and I'm ready to throw my laptop out the window because of it's PC-ness. (Vista sucks, yes it does.) They're better to work with, have less of a security risk, have less problems software and hardware-wise than a PC, and Apple tends to make things pretty.
The price tag on a good Mac is more than on a PC, but they go longer and work better, so it is worth it. But if you do end up getting a PC, my advice is to get an Alienware or a Fugitsu and run a version of Linux on it. It's actually an easy OS to use once you learn it, and has so many less problems than Windows.
(I wouldn't have a PC or Windows, but I didn't buy my computer. I thank my mom for it, though!)