Hmm, well no matter the model number, at 46", plasma is definitely going to better than LCD for SD sources (that is anything below high definition like HD-DVD, Blu-Ray, HD gaming with Xbox 360 and PS3, Sky HD etc). So if that's what you're going to be watching, you'd be better off looking at the plasma versions of the different manufacturers such as the Panasonic and Pioneer screens at both 42" and 50" size or even the Samsung PS50Q97HDX.
EDIT - sorry, completely missed out the Panasonic 46" plasmas coming out, like the TH46PZ80B and the TH46PZ85B which are obviously right on the money for your screen size.No reviews yet (that I trust) on either, so would take the time to go see them in action when they come out to decide if I were you.