I have the 650 with its swiveling plastic base sitting on a heavy steel and glass Sanus stand that rests on a carpeted floor. If I touch the tv it will wobble front to back. If I had young children I'd be very worried.
I can only guess that the 750 has a similar plastic base only non-swiveling?
Have you tried touching a Panny plasma to see how stable it is?
I am considering both the 650 and 750 52" LCD models. The TV's both look great and have a loyal following from just about every forum and review source out there. One thing that i am concerned about from checking out the 650 is the swivel base - it seems very unstable. A slight tap of my finger on the top edge of the TV seems to leave the TV wobbling up and down. I am concerned that a kid running by the entertainment center, or even opening and closing the doors below to get to DVD players etc would cause it to wobble (which would drive me crazy!). Has anyone else experienced this or have an opinion?
Also - was looking at the 750 version with the non-swivel base - unfortunatly the stores around here do not show it as a floor display, so i can't get a good feel for how stable it is compared to the 650, the price is less than a 100$ more, so price is not an issue, but i would be willing to pay the difference if it were much more stable. My wife really wants to get the Panasonic 50" 800u plasma which has a massive solid base, but i love everything else about the Samsungs. Any help would be very much appreciated! Thanks in advance.
Ed

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic