Get a plasma.
No seriously. Get a plasma.
I went thru the exact same thing with the 55" Vizio LCD. Even worse I ordered it offline. Which meant to return it I had to put this big azz tv back in the box, get it to FedEx/UPS and ship it back. And thats exactly what I did. I asked a friend with a pickup truck to come over, boxed up the TV and took it down 3 floors and then drove an hour to pay $120 bucks to send it back FedEx Ground. I was refunded my $1200 about 2 weeks later. And I went and bought a plasma of equal size for about $1000. I could not be happier with the plasma!!
Hard lesson to learn, but you'll never catch me buying a big screen LCD TV again. My eyes are entirely too sensitive to the motion blur, motion smoothing, "soap opera" effect. I can notice it instantly, and it always turns me off. Even walking thru Costco just 4 days ago.. I could instantly tell which big TV's were LCD and which were Plasma. I must admit I do have a small 37" 1080p LCD TV in the bedroom that seems to have no problems with motion. And its only 60hz. So I agree that only 120/240hz LCD have this problem or that screen size may possibly play a factor. I also ONLY notice this problem on big screen (50"+) LCD's. Either way.. you want big screen tv for gaming? Get. A. Plasma.