I am soooo excited about 4K and how quickly the price is dropping. 55" is about the smallest you want to go for your average living room (any smaller and there is very little difference between 4K and 1080p), but I am holding out hope for a 40-45" 4K display for use as an oversized computer monitor. First company to do such a display that can hit 60Hz and treat the whole screen as a single display for ~$1000 will get my business.
I may have to wait a bit before this happens, but considering how quickly the prices have dropped since their introduction last November, I can't imagine that it will take more than a few years. I'll have to wait a few years before single GPUs can properly drive 4K displays above 30fps anyways, so I suppose I can sit back and wait patiently.