Something i learned a long time ago is not to "wait for the next big thing" when it comes to technology.
I remember reading somewhere that as soon as you buy a TV/PC/Laptop etc it is already 6 months out of date due to the pace of progression.
I bought a TV a couple of years ago that apparently had the best image quality for an LCD. Even now 2 yrs later everyone that comes to my house and watches it says the picture quality is brilliant. That's with just Sky HD, Blu-ray is even better. Whilst we are on about Sky HD, their HD quality, as mentioned, is dire. Initially i thought my TV was either faulty or set up wrong. I had it set up properly and the guy that did it mentioned that Sky HD is heavily compressed hence the fact i was getting the poor quality image on HD Channels. 720p & 1080i on Sky are nothing like what they should be. No doubt Murdoch's mucka will say it is but it isnt.
These Lentic 4K tv's (lentic is the term currently used for 3D without Glasses) are way off being in most people's budget at the moment unless your first name happens to be Sheikh. I would have quite happily bought that 70" TV, moved the 40" to the Bedroom and enjoyed the hooooooge image for the next 5 years. 2 things stopped me, one being i would be sat too close as our lounge is not wide enough. I could block the patio doors at one end with it but that would upset mine and SWMBO's fung schu. The second thing was SWMBO said no
Seriously if you after a new TV and have a room big enough for the 70" one then get yourself down to costco. They are £2399 elsewhere!