Black switches are sometimes considered the best switches for FPS games, while tactile switches like blue or browns better for RTS and similar games. I have only used browns, which work great for the FPS games I play. Like the people before me in this post have mentioned, there really isn't a wrong switch. Any switch can do anything, so that makes deciding upon a switch personal preference. Sure, if you ONLY use your keyboard to play FPS games then black switches may be the best because if the linear action. But many don't like the black switches because many people experience fatigue when typing on them. While on the other hand some prefer to the feel and the weight of the black switches for typing. So like I said, it's all personal preference.
My advice is to try out as many of the switches as possible, and then pick which ever one feels the best to you. But if you find it hard to get to that many switches, most would say brown and blue are the best switches to start with. Many also advise to stay away from switches like clears, reds, and blacks because many seem to either love or hate them.