The newest technology in TVs is clearly 4K...no pun intended! That's because 4K (aka Ultra HD) is simply HD quality at twice the number of pixels both horizontally AND vertically. So 4K is HD resolution multiplied times four! Put another way, 4K compresses four times the pixels in the same amount of space that Hi Def does.
Why is that important? Well, if you prefer smaller screens and have a smaller room where you watch TV, its not important, quite frankly. But the clear trend is people buying ever larger TVs.
Some TVs might feel like jumbotrons in an ordinary room! But that kind of size is what it takes to have a great media room or home theater experience. The problem is when the same number of HD pixels are stretched over increasingly larger formats, the appearance can become ever so slightly grainier. 4K solves that! There's also 8K out there that doubles resolution yet again to near IMAX clarity, but that's another story.
Like any newly released technology, most media content isn't yet formatted for that resolution, but the content IS already out there. Blu-rays are already capable of 4K content but nearly all agree the future of the 4K advancement is in streaming video. Netflix, which already shoots its successful original series, House of Cards, in 4K recently offered that it plans to deliver 4K content within the next two years. Sony already has a big investment in 4K by way of the cameras they sell to the movie and television industries and the projectors they produce for theaters.
So 4K is not a fad, but neither is it for everyone right now. Still, when you consider "upsizing" your video experience, you will definitely want to keep 4K as a strong contender in your plans.