I only have the 46B750 but I do own a Wii, PS3 and Xbox 360.
All LCDs will have lag and the motion processing is there because most people watch TV/DVD/Movies and not game. If you are looking for lower lag solution you can get a Samsung 30" Monitor at Newegg or other places which may be a better solution
On the Wii we mostly play the following:
Tiger Woods Golf
On the PS3, we mostly play the...