It's a question we've been asking ourselves for ages... months even. Should I buy a PS4 or should I buy an Xbox One? I am here to tell you that, without a doubt in my mind, you should build a PC.
After that's all taken care of, you should play Assassin's Creed 4 on it. I know, I'm as surprised as you are, but it's the best one since AC2.
See ya!