Hi Tony,
I've been researching the same TV's as you for a few months now, and have come down to the final week before purchase time. I too am confused as to whether the LZD85 or LZD800 is worth the extra pennies ontop of what the LZD80 in terms of getting anything more out of my PS3 (which I will be buying at the same time for Blue-Ray and HD gaming).
In my opinion though, using the Panasonic 'comparison' functions on the televisions, the 85 model has a few more film bits and pieces to it. As an amature, I have no clue what they mean, but it sold it for me I think. I'm definately going with the 85 model mate. I am also buying it from John Lewis and submitting a price match to PC World, who are doing them for over a hundred cheaper. They should accept this. John Lewis give the TV with the usual 5-yea guarentee , plus a really nice looking, black glass stand.
Not sure that's any use dude, but hope it might settle your mind a bit. I guess spending this much money for us both - you want to make the right decision. According to reviews though, the LZD85 is a superb television and we won't be unhappy.