I'm in the same boat as well, I've been eyeing the Sony KDL-55W900A, in all the reviews I've read so far it seems to get praised for its very low input-lag and color reproduction, I've seen it in person, both motion and picture look great, but I couldn't test the input lag. Downside to some might be the size limit tops at 55", it's the perfect size for my room. Let me know what you think!
From what I've read that's currently rated as the top TV for gaming, and has a "Blistering Fast" input lag rating at 19ms and the model right below it, the Sony KDL-55W802A comes in at 17ms of lag. Seems a lot of the Plasma's are up in the 60ms range. They may give a better picture but is it at a trade off??
I'm currently researching gaming TV's in the 40"-46" range right now for my PS4.