I would just like to drop a note of thanks to everyone on this thread for their informative and knowledgable comments.
Our 6 year old Sony 50" Rear projection finally died last week (optical block). Mrs Blackmme didn't want to lash out a lot of money without feeling that we had gotten a big upgrade (size therefore being a greater requirement than image quality).
I was certain I didn't want to spend more than a £1000, I could not care less about 3D and we have a PS3 to handle most 'smart TV' capability.
These criteria and constraints removed at a stroke most of the very excellent LED 55" inchers from Panasonic, LG, Sony and Samsung. We were therefore taking a look at the LG and Samsung Plasma's around 50" for about £700 to £800, pretty good TV's to my eye's but without much in the way of the 'wow factor'. I took a look at the Sharp and even with shop settings in Currys and Comet it looked excellent. The sales guy had absolutely 0% interest in talking about the Sharp, he said it was 'old technology' and 'not very good' luckily I delved a little further through you guys and on Saturday we weighed up our options between John Lewis and Comet. Normally a pretty straightforward decision I guess but JL couldn't deliver for nearly a week so we went to Comet and did a bit of a deal taking ownership immediately and off setting the loss of the 5 year warranty with 3 years of cover for £60 (yes I'm impatiant as my accountant wife was happy to point out)

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Suffice to say I think the Sharp might be my most satisfying AV purchase in all of my 43 years. I'm blown away by just how much the technology has come on in 6 years and by the quality of the Sharp (using the settings taken from above). Even the SD is acceptable DVD via the PS3 is excellent and as for Blu Ray it's just incredible!
So once again thanks to all on here for their excellent guidance it's truly appreciated.
Regards Mike