wikipedia
On smaller CRT monitors (14“) few people notice any change above 60–72 Hz. On larger CRT monitors (17”, 19") most people would experience mild discomfort unless the refresh is set to a more comfortable 85 Hz or higher. 100 Hz is comfortable for most people. However, LCD monitors do not suffer from the same problems as their CRT predecessors and the refresh rate simply does not mean the same. LCD or TFT monitors will provide excellent quality and resolution at 60–Hz. The more important issue for a TFT or LCD monitor is its Response Time, Image Brightness and Image Contrast Ratio.