Jumped on this in exchange for a Panasonic 55UT50 plasma I ordered a couple weeks ago. The buzzing drove me nuts, and the tech couldn't fix it.
LED was more what I was leaning toward when I started shopping around since I do a lot of gaming and watch a lot of ESPN--so worrying with IR on the plasma was another concern (and something that was starting to annoy me too).
IPS panel (In-Plane Switching technology) is a technology used for liquid crystal displays (LCDs). It was invented to solve the main limitations of TN-matrices at the time: relatively slow response, small viewing angles and low-quality color reproduction. In-Plane Switching involves arranging and switching the molecules of the liquid crystal (LC) layer between the glass substrates essentially in a plane parallel to these glass plates.
HOWEVER, be warned: Not all IPS are created equal, and some of the wide angle viewing claims of the ET5 I find to be wrong IRL. Many Sony's, for instance, do not employ IPS and beat the IPS panels I've seen hands-down.
P-1 CUR ALLOC 20195.....5805M
Viewing angles are one thing I've never cared about. I don't have or want kids, and thus have no reason to want a big house, so we'll always be in condos or small houses where the only place to watch TV is the couch directly in front of it.