Beware you will get many answers with no real information beyond "mac's are crap" or "pc's are stupid".
Logically they both do a similar job. They both provide access to plenty of software and functions. The biggest differences however are as follows:
Mac's are frequently more reliable. This is not because they are built better, or because they have a better operating system, but because they are quite simply all the same. Apple control the hardware; all Macbook Model X's are the same. PC's however vary, the likelihood that you will have the exact same hardware setup as another user is minimal. This variation means that if you have an incompatibility or issue resolving it is far more complicated.
That's not to say it's overly complicated with a PC. In fact you're more likely to find that the support for PC users is beyond that for Mac. I'm speaking of course about third-party support; hoping to get any help from either Apple or Microsoft will be minimal and expensive.
If you're after more options, more choice, and to be honest more software- I'd say get a PC. Mac's are ok, don't get me wrong, but given the choice of the 2 I'd prefer a Windows OS (if not a Linux OS). These options are only available for PC's. That's technically not true as many Linux Distro's are available for Mac's; and Apple's Bootcamp does allow Windows to be installed on a Mac (although with some limitations).
If you're not planning on running Linux, or dual booting anything, then the OS choice really is OSX vs Windows. In this battle I'd argue Windows; and that's not because OSX is poor or lacking; just because I find Windows to be more customizable and far more supported by games, and many software providers.
To conclude; get a PC, but not because there's anything wrong with Mac's, but because a PC will be more customizable, more personal, and have a wider array of software available.