Yep! I was trying to tell you about the setup CD above, and also that MANY retail stores like the ones you listed just hang them up on the mounts, plug 'em in, and let them show whatever picture is available. They usually never set them up correctly, so it is near impossible to compare them. Plus, if you have an EDTV and HDTV side by side, how would you even KNOW how the pics compare?
I read on the forums that someone went in to look at plasmas and told the sales consultant to try plugging in an HD signal to an EDTV. The consultant didn't believe it would work, but low and behold, the picture looked almost identical to the HDTV! Now, keep in mind, side by side, both set up properly, both the same size, an EDTV and HDTV, both using the best signal each can accept (which may even be an HD signal on the EDTV), the HDTV set will probably look better... it is made for the HD signal. Both TVs with an analog signal, and the EDTV will probably look better. Either way, HDTV plasma is going to be quite a bit more than an EDTV set. It's up to you as to how you want to spend your money!
As for just about any plasma being good if set up correctly... it may possibly be true, but I would still look at reviews on the models you are looking at, just to make sure it is at least above average. Many reviews (in forums) are usually sparked by someone either extremely liking something, or extremely NOT liking something... you usually don't get the ones in between, so many reviews are somewhat bias... unless it is from a reliable source (magazine, online magazine, review publication). DO look for quality control issues, especially on what seem to be cheaper sets. Again, you can't go wrong with Panasonic, Hitachi, Fujitsu, and a few others. I haven't heard very good things about Sampo's or Akai's, but it may just be from the one or two bad experiences that you do hear anything about them.