I do realize it is an old thread, but I figured it won't hurt to write my input.
The most dynamic speakers I have heard are the ones I am using at this time, PIERRE ETIENNE LEON M II. You have to hear these.
The B & W 801 S3, I don't want to rule them out, but I feel they were a very large for my mid size room.
The other thing is that you have to have a good amp as well, or you would not be able to hear the full dynamics of your speakers.