if used for occasional gaming then GT60 minimum.
if no gaming use at all then you may as well go ST60 (has more input lagg) and a bigger screen size.
although you would be a fool to go for these models imo when the 51" E8000 is only £899 from John Lewis.
yes it's a Samsung, but it has the far better "smart" tv features, built in skype camera (worth at least £100+ if you want the same thing on a panasonic), etc, etc.
I have the 51" D8000 which is the older gen version of the E8000 as well as a 50" GT50 which is the older gen version of the GT60.
both are cracking sets and the newer E8000 and GT60 will be even better.
go for the 51" E8000 for £899 from John Lewis.
as for PQ Samsung are on par with Panasonic, Panasonic have better black levels, but Samsung have better panels in regard to 50hz flicker bug, DFC (dynamic false contouring) and banding.
go for the samsung and this is coming from someone who has pretty much recommended panny's on here to everyone.
also with the spare £100 - put it towards one of these
http://forums.overclockers.co.uk/showthread.php?t=18538496
i got mine from supermarket for £159 using a £10 online voucher code from hotukdeals.
the built in speakers on any modern flat screen tv are crap.
here is a link to the E8000
http://www.johnlewis.com/samsung-ps...ch-with-freeview-hd-and-2x-3d-glasses/p505127