I had the same debate, and ended up buying the Samsung.
After seeing the two side by side, the choice was clear.
The Samsung had a better picture, and the Sony looked to big, especially with the speakers sticking out like wings. I've had no issues with the Samsung, but I have discovered two things with this TV.
HDMI gives a better picture on standard def TV over component, HDMI and component equal on HDTV.
When I ran the sound out of my cable box directly to my surround sound receiver, there was a delay. Running the sound out of the TV via digital fiber optic to the the receiver solved this.
Awesome picture with all sources, especially digital and HD.