Cam, is you DVD an upconverting player? If not, I can see a true 480 image not looking great on a good TV. The TV's internal scaler may not be up to par, or the play may just suck? If it is upconverted, then the problem might be with the player. Do you have access to a Blu-Ray player? If so, try that through the same input. If that looks fine, it is probably not the TV. If that looks bad however, call the store and complain.

Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire