Diphan, I'm not sure where you are with your purchase decision, but I read this thread with interest since I have been seriously considering the Panasonic HDTV set you mentioned in your original post. I live in the UK and therefore not all the models mentioned here will be identical in the US or elsewhere, but the basic principles will still apply. The bottom line for me is, find a dealer that you trust, and that can demo the two or three sets our are interested in side by side, preferably with the type or content that you intend to view today and that you think you will watch in the foreseeable future.
I too have been bewildered over the past few weeks by the huge number of brands, models, technologies and functions available on HDTVs. My main reason for changing my current Sony CRT is that I want a bigger screen to watch movies on - without a hefty satellite subscription I can't even get HD TV reception so the HD capability is a secondary consideration for me, although something I need a keep an eye on for the future. I have a rather large investment in (standard definition) DVDs and there whilst it is important that my purchase is reasonably future proof (has support for HDTV and HD-DVD\Blu-Ray) , but it is just as important that I can watch my existing movie collection and SD channels presented well on a large screen. Whilst 1080p is the latest big thing ad must have, you should bear in mind that the larger HD sets do not always do a great job of upscaling SD content, so if this is important to you make sure you are happy with the results through a demo before you buy, otherwise you might be frustrated when you get your new set home and your non-HD viewing is not as good as you expected. Also, not many broadcasters are are currently (or even planning ) 1080p broadcast. That is certainly true for the UK, not sure about the US, which I know is more advanced in its HDTV adoption. But since the technical constrains will be the same - i.e. the huge bandwidth requirement of a full 1080p feed, then I think that 720p for sport and 1080i for other viewing will be the dominant HD content for years to come. Not even the new generation of high definition DVD (HD-DVD/BRD) will guarantee 1080p - though they are very capable of it, it will be up to the studios to adopt that resolution. Since the players and the moves are very expensive at the moment I don't see a very compelling reason to spend an extra $1k to get a 1080p capable set just for the sake of it. Having said that if a model you choose happens to be 1080p and does all the rest you need to satisfaction then you have another potential buffer against future developments.
Having said that, based on the limited demo I had in a local store yesterday, I do not think that you would be disappointed with the Panasonic (despite not being 1080p). I was certainly impressed, to the point where I was ready to make a purchase. Whilst it may not be the best 42" set in the world, it is certainly very good for the price and on the whole that is good enough for me. The very best plasma is a Pioneer, but is it worth the extra $6k? I think not. At the end of the day there will always be something better on the horizon, but for me the price/technology curve is starting to get to a point where it makes sense to take the plunge. I'm working on the rational that I will buy something very good now (rather than the absolute best) since the saving I will make over paying the premium on the absolute best will help greatly towards the replacement down the road when something better than what I buy today will surely be available for much less. That's the nature of hi-tech 
The rest of this story is about a recent visit to my local TV store, since I think it illustrates the important of reliable trustworthy advice from the specialist who sell this equipment. Please keep in mind that I live in a rural area where large dealers are few and far between, and I have known the people who run this store for over 12 years and they have a reputation locally for providing excellent advice, but sadly not rock bottom prices. Nevertheless I am happy to pay the premium for the honest and unbiased advice I received.
I went to the store to get a demo of a TH42PX60. Unfortunately that set was in the window display so I was only able to get a demo of the older 37" version of this screen. A comparison was made with a 40" 6th generation Sony LCD (I don't recall the model, but it was HD capable up to 1080i). I'd explain my requirements and criteria to the shopkeeper and he talked me through the pros and cons of each technology type, demonstrated a few DVDs playing though the HDMI and SCART etc., and explained how the competing LCD and Plasma generations leapfrog each other in terms of addressing various issues such as burn in, refresh (fast motion response) colour rendition etc. I asked him about burn in, and he said that indeed it used to be an issue with the older generation Plasmas, but that he had not had a single set returned because of that (other breakdown faults, yes, but not burn in). He also mentioned that LCD was quickly catching up with Plasma in terms of displaying fast motion. I asked him for advice and he suggested that for the money TH42PX60 would probably be the best option, since the saving over the TH42PX600 would allow me to buy a HDMI equipped DVD player which combined whit the new set would give better results from DVD than the TH42PX600 with my existing SCART equipped DVD player. Given that TH42PX60 is $700 (
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