Panasonic 50 gt50
panasonic 55 st50
I would go for the Paasonic 55ST50 based on its stellar and premium performance. And it has the best black levels.
AV: OLED LG 55EA980w TV, Samsung 7500bd, Pioneer Sc-LX81 amp, B&W FPM Series, B&W PV1 Sub. Gadgets: iPhone 5C, iPad 2, Beats Studio Phones. B&W Zeppelin Air.
Just bought 55HX853, VERY happy