There are 2 reasons that justify buying a PC :
You are a hardcore gamer
You have limited money
If this is not your case, buy a mac.
People saying there are more programs available for PC, you do realize this is a skiing forum where the average age of user is 14. No one here needs the financial or engineering softwares only compatible with PC and even if it was the case, bootcamp would do the job.
Now let's be honest, the hardware is always more or less the same between mac and PC, usually cheaper for PCs (that's a + for PC). The reason mac is better (yes it is better) is the god damn operating system. No matter how you present it, windows has been total crap since windows 98, it's constantly crashing, settings change by themselves, etc. I did not realized it myself before i switched to mac years ago. OS X is incredibly stable, extremely user friendly and so intuitive that you learn pretty much everything there is to know in 2 weeks.
Yes, mac are more expensive. If you want to pay less and are ok with constant frustration, go for a PC. If you want to pitch in a couple more 100 bills, get a mac, no one regrets switching to mac.