I'm going to back track on what I said a bit, (cus I wasnt thinking at the time).
Right look at it like this, 8ms is 8/1000th of a sec. A typical LCD panel only refreshes at 60 Hz, which is 1/60th of a second.
Ghosting is caused by the image processor (all LCDs have them) not being able to keep up with the new frame (one every 1/60th of a second) and therefore your image tends to "smear" across the screen. The less work you give your video processor to do, the less ghosting you will get.
When I first got my 6ms 32" Sharp LCD TV, I thought it was the other way round, I had loads of enhancements running and the picture looked shit, basically.
Then I was told how they really work, my TV is now running with every enhancement and picture sharpness etc off. All colour brightness settings are default, and do you know what, it makes standard def TV look like HD, the picture is fantastic, and NO GHOSTING!
So to go back to the reasoning behind why I could see a difference between a 8ms 19" and my 5ms 22". That was because the 5ms 22" is a Crystalbrite Acer, and the 19" was a cheap as possible Hanspree.
The reason there was a difference will be that the much cheaper video processor in the Hanspree cant keep up with each new frame coming in so gives ghosting.
So its not really about Response time, but the quality of the monitor you are buying and the way its setup