DO try and beat them down on price.If they say they can't negotiate then say thanks and go to the next dealer.The mom and pop dealers will work with you.
From what I was told,not in any specific order,the best sets now are Hitachi,Mistubishi,Toshiba,Sony(nothing American about those names unfortunately...).Pioneer is supposed to be a very good product as well.Happy shopping,toys for big kids are fun to buy!
PS/Get a surround sound if you can.Totally enhances the viewing pleasure immensly.