Thanks everyone for your replies. I actually exchanged the panny for another one. There's still a faint blob in the same place, but it's very tiny and only noticable on a bright white background, and then not much. Perhaps there something magnetic going on, but the improvement between the two...
About a month ago I decided to upgrade my 10-year-old 25" RCA set. The picture was fine, although I did notice a darkish vertical band on the left when the scene was dark. But given the resolution of the set it really wasn't noticeable. So, I explored this and other forums, as well as visited...