I cant imagine what the problem could be! I can only relay similar trouble that my brother in law was having with his HD setup (TV) and his DirecTv Satellite box. Apparently his sattellite was somewhat faster than his television as far as relaying commands and/or information goes. Due to this his TV would lag on channels and take a few seconds to display the image without audio, then soon thereafter with audio. This would happen every time he changed a channel. I will second what Shoeberto said about synchronization. The standard def AV cables should be sufficient as well as your system, the only thing I can attribute the problem to is the TV. The Vizio's refresh rate might be slow for standard definition since it is HD on a budget due to the market Vizio is trying to satisfy. Try an HD cable and see what happens.
I know this is an old thread but I wanted to put in my two cents. Well maybe just a cent and a half. Hope its all resolved!