Apologies in advance for the long post!!!
Right guys as I have already stated Bumtious came round yesterday and he spent quite a few hours exploring the set, along with me, and getting some really great results.
Before I move on to a report I would like to qualify my views by saying that I work in TV. I am a Playout Director for BBC Television, here in the UK, and I monitor Broadcast TV, including HD, for a living. I, therefore, like to think I know what good accurate PQ is. On top of this I have also made short films and produced event videos, such as those you get at weddings, in the past and I am confident that I know what I am talking about. Having said that I do not know enough about TV calibration or have the right equipment to get the results Bumtious did from this TV myself
Anyways, first of all I was never impressed with THX mode. I would agree with some that out of the box it does a pretty nice job, well after a few hundred hours at least, but just not good enough. IMHO the image in THX mode (as well as all the other pre-sets) had very washed out colours, a green tinge in the greyscale (people looked jaundice and whites green or slightly blue), no where near as black blacks as I am now know this TV can produce and the dynamic contrast was not great. I would also say that the depth of field it produced was rather limited compared to other TV's I have seen in HD. All of the above were made worse because my old Samsung UE55D8000 did all these nicely. On top of all these the set is nowhere near as bright as it should be, but IMO as bright as I need it

I would also like to add that my set suffered from the usual posterization seen on Panasonic sets.
Right, so what has calibration addressed? Well, in my opinion, everything but the brightness.
Colours are now as vibrant and realistic as I have seen on a plasma and even match my old Samsung, which were the best I have seen on any TV for vibrancy. Skin tones are as accurate as I have seen, since the Pioneers, and the whole set when playing the right source looks Filmic in its colours. Reds pop better than I have seen and so do all the other colours.

Colours no longer look washed out and are as accurate as the broadcast monitors I have at work but far more vibrant.
The Green tinge seen in THX mode is completely gone and white now looks white, with everything in the grayscale perfect. The contrast has been mightily improved and blacks look amazing, with shadow detail in the dark simply stunning. IMO the blacks in THX mode are just too grey and the effect can easily bee seen in the black bars on letter-boxed movies. Bumptious has clearly rectified this and in doing so addressed my other gripe, which was the dynamic contrast and HD depth of field. The set now pops in the way the Samsung did and HD looks 3D.
Another thing that I am must happier with is the perceived improvement posterisation. This is now no longer an issue. It is still there but nowhere near as evident as in all the other pre-sets and a welcome bonus to all of the above. I would also like to add that without a firmware update I am not seeing many FBr's. It could totally be a coincidence, especially seeing as I wasn't seeing them much anyway, but I haven't seen any since the set was finished being calibrated.
As you can probably tell I am very happy with my calibration. As I said to Bumtious, this set is the first I have seen that can come close to looking as impressive, in HD as my broadcast monitors at work. Everything just looks as it should do and I am very happy and worth every penny. The only thing that has disappointed me is the overall brightness in the set during the day. Bumtious worked hard to bring this up to it’s highest and he simply couldn’t do it as it just cannot be done.. We did lots of tests and made some interesting findings but maybe he would prefer to chime in with this. He will be able to explain better than I.
Before people ask, I’ve decided not to share the settings and if Bumptious wants to share his report then that’s fine by me. Thanks so much mate it all looks great, oh and guys he also calibrated 3D and wow Avatar and Gullivers travels are the best I have ever seen. calibration is worthit for the 3D improvements alone.