Iam planning to buy a 42" Plasma EDTV. Iam connected to digital cable. I have been reading about aspect ratios (4:3 vs 16:9 Widescreen) My question: Will the image ALWAYS be widescrren or will it be a conventional image with bars on the sides and top and bottom? Do I need a special feature on the TV to convert the images to widescreen? Please help and explain. The people at the stores I have gone to don't seem to know anything!