High Refresh Rate: You want something with at least 120HZ native refresh. Beware that they will try to overadvertise with words like "Aquomotion", "Smooth Motion" and stuff like that which will be double the actual refresh rate . Native refresh @ 120HZ is the absolute minimum you should consider.
HDMI with ARC: High definition multimedia interface with AUDIO RETURN CHANNEL. This lets you output from your TV to a: Soundbar, Audio System, Multimedia Reciever, with just one HDMI cable in Dolby, DTS, 7.1 channel resolution in digital. Optical "SPDIF" outputs are no longer good enough.
The legs on these TV nowadays are set at the corners to save the manufacturer some money versus the stand that used to be in the middle of the TV. With the stand in the middle, you could get a big TV and not have to have furniture as wide as the TV that the TV could sit on. No more. Now your furniture has to be as wide as the TV or you must wall mount. This is just something to think about.
High Speed HDMI high speed 60HZ input with HDMI version 2.0 and HDCP version 2.2:
HDMI version 2.0 is faster and will accommodate the next generation blu-ray 4k players. HDCP, High Definition Content Protection version 2.2 will enable you to watch the content. These two items "future proof" your TV.
Back Light Full Array dimming versus Edge Lit.
Full Array puts the LEDs directly behind the picture and can dim out in individual blocks (up to 72 so far) for higher contract and no splotchy screen during complete black.
Edge Lit = thinner TV with some capability for block dimming.
my current favorite is the VIZIO "M" series TV available at Wal-mart, Best Buy, and Sams.