Almost any LED that you purchase today will have a better picture than your 7 year old Vizio LCD, short of buying something really, really cheap like a TCL, Westinghouse, Philips, etc.
any Vizio, LG, Samsung, Panasonic, Toshiba, Sony, etc will look great compared to your old LCD. I personally love LG, because their picture quality is on par with Samsung/Sony but they are priced closer to a Vizio, LG has the best price/performance value right now IMHO. Both my 50" Plasma and my 55" LED are LG, and they look spectacular.