So I give a very concise response. It's the same every time. "It depends."
Honestly, this question was easier to answer in years gone by than it is in 2015. Years ago, Mac and Windows were such different platforms that choosing one amounted to discovering which one had the software you needed. You need a video editor? Get a Mac. You need Microsoft Office? Go Windows. You checked the boxes, and at the end, the decision was made for you.
Now, basically every major piece of software has a version for both. If not, there's another program that does the same thing on the other platform.
There also used to be a security argument for choosing one over the other, but there are Mac viruses now that get in the same ways that Windows viruses do. All of them can be avoided on either platform with a little coaching on what to look out for.
Functionally, Mac and Windows are closer to identical now than they have ever been. Websites look and act the same in just about every browser. There's apps for drawing, movie making, audio recording, note taking, and anything else you can think of. The only real differences are in the look and feel.
It really does come down to budget and personal preference. If you need a computer for writing papers and looking up things online with a $300 maximum budget, you'll be buying a Windows computer. It will serve you well and you will get to the same Internet that everyone else gets to. If you have the funding for a higher-end machine, buy whichever you like. You decision will not limit you whichever way you go.