matthewpiano:Darren
I'd stick with the 46Z5800. Its a good deal and the Freesat versions of the existing range will be continuing alongside the new Freeview and Freeview HD ranges so it won't even be obsolete for a few months yet. There are no plans for Freesat versions of the new models. Bear in mind, also, that the first new releases will be the lower range models and that the top end stuff like the Z5500 replacement will follow a little later.
The Z5800 is a cracking TV with really good motion tracking, excellent detail in the dark areas, and very good processing to make the best of an SD signal. The Bravia Engine 3 processor will continue into the new range (there is no BE4), and it has proved to be very good at its job.
Having said that, I haven't seen the new models in the flesh yet so please bear that in mind when reading this reply.
In terms of the X4500 Vs Z5800 comparison other than what I have said before I would advise taking another look at them side by side. Personally I would still go with the Z series. hi matthew cheers for your reply when i get it all set up ill post my views. you have been a great help, this comes with the 550 blueray player just wondered if i brought the 760 instead is a big step up in PQ to the 550