Refresh rates and response times are different concepts both of which affect the image quality. Response time is most important with LCD screens. It is the time is takes for one of the individual color pixels on your screen to turn on or off. The larger the number, the longer it will take for the pixel to switch. Long response times can cause what is known “image smearing.” This is most noticeable on fast action scenes and sports where movement can appear to be blurred.
This happens because the screen cannot physically keep up with the movement. Many early LCD screens suffered from this because they were based on computer screen technology. Most computer applications, with the notable exception of games, don’t have fast moving images so this is not a problem. Today, apart from the cheapest of brands, response times are much better and not likely to cause an issue. Current screens have response times of between 4 and 8 milliseconds. Going forward, the new OLED technologies have response times of 0.01 milliseconds. However these are currently restricted to small screens and are very expensive.
Refresh rate refers to how many frames of information you see on your screen every second. In the US, a progressive HD image effectively shows you 60 images per second i.e 60 Hertz. Some screens now offer refresh rates of 120Hz or now even 240Hz. This is done by analyzing the two consecutive images and then creating a new image which is half way between the two broadcast images.
The idea is that the more images you see per second, the sharper the picture. Because some of these technologies work better than others, a screen with a higher refresh rate won’t always produce a better image. You should see the screen in action or at least read a review from a reputable source before investing the extra money. Again the difference will be more noticeable with action scenes and sport, but you need to make sure that the image doesn’t look unnatural.
It is also worth noting that cinema films are actually shown at 24 frames-per-second and that better Blu-ray players and screens are now designed to handle this much slower refresh rate. This provides you with an experience much more akin to that in a real cinema. We are all so used to cinema images that this lower refresh rate and the odd bit of grain is actually often preferable to the precision of video.
You will want to see the big football game in great detail. In fact I was at the Chargers/Saints Game in London and to be honest, I know I would have seen more watching it on HD at home. But if you are watching a big screen epic you want to recreate the magic of film.