On one side, there's 4K: four times the resolution of your current TV. LG, Sony, JVC, and others have all announced or shown upcoming 4K displays.
On the other, there's OLED: Organic Light-Emitting Diode. Significantly better picture quality than your current TV, plus lower energy consumption, and even thinner cabinets.
So what's more exciting?
With 4K, there are many potential benefits. You can sit closer to your TV, for one, without ever seeing pixels. Or you can get a much larger TV for the same reason. If you sit close enough...