The main thing I would point out here is that your Hz should match your frame rate. Example if you are able to game at 1920*1080 at 75 fps than a monitor with a refresh rate above 60 would be helpful. However if you are playing at 2560*1600 and only getting 45 fps there is no point in going over 60 Hz anyway. If your fps is above your refresh rate you will see "tearing" in the game as the monitor tries to keep up with the graphics display.