text: Basically if you are going to do any gaming or applications that require a fast response time you will want something that has a response time of less than or around 16ms and if it isn't you may experience a ghosting effect which causes blurry images on fast moving sequences.  But I'll tell you this is subjective.  My 17" Samsung monitor has a refresh rate of 35ms and I have never noticed any ghosting with games such as Half Life 2 or Doom 3.  Some people are more sensitive to it than others so if you aren't sure look at the monitor in a store before you buy.