What's wrong with my new LCD?

It could be your settings/or not. I do know most stores have a better feed than you might have at home. You might stroll on over to ---avs.com---see if your tv has a following. (Most every tv has a thread at that site)--Read and then ask over there. Many brands have recommendation for out -of- the-box,settings.)---These are within a thread for that brand and model,posted by owners of your set.---Lotta smart guys there.

check all your cable connections

Yes if you purchased it to watch regular cable then what you are seeing is normal, crap in is very visible on new HIDEF units, great idea to try a DVD and hopefully Hi Def material....do you have digital cable or Direct TV?, Standard analog basic cable stations look like crap on my HDTV,

If you are watching a standard def picture it will look like that. How is it with a high def signal. Or a dvd.

give it time to burn in.Maybe it needs a few hours..If not bring it back!!!!