There are some interesting developments in the gaming LCD space (BENQ, ASUS) that are focusing on reduction of motion blur in LCDs at 120hz. You can basically get plasma quality motion resolution by using strobing LCD backlights.
Check it out here:
I bring it up because one major area where Plasma/OLED beats LCD is motion resolution. If I can get an LCD with accurate colors AND good motion resolution, an OLED looks a lot less tempting. Note, my plasma smokes my LCD in PixPerAn motion resolution tests.
Now with most over-compressed broadcast TV rendering motion completely blurry due to compression artifacts, LCD has gotten away with having poor motion resolution. But if you do a side by side TV comparison with a very high bit rate 1080p60 source showing a lot of motion, OLED will likely smoke the best LCDs. High bit rate 1080p at 60fps is what I'm looking for in content. And I think 1080p@60fps will become the real UHDTV because millions of TVs support it and you will be able to see the difference unlike 4K.
4K TVs are basically 3D 2.0. It's being pushed down uneducated consumers' throats, again. Now I would gladly take a 30 inch 4K computer monitor that sits 2 feet away from my face, but for a 55'' TV 12' away, it's pointless. I would also much prefer a 4K OLED monitor as you're not limited to the blu-ray/HDTV color space.