Since we are within a month or two for most of the 2015 new 4k releases I would definitely wait. I am excited to see this year's model improvements as opposed to all prior years, at least on paper & specs & a few miniscule reviews from CES & others. This year I plan to retire a Qualia 006 70" behemoth that is 10 years old. If money is not an issue for you within your screen size, based upon what we currently know I would believe any of the below are awesome choices.
As far as what roller11 said about the 4:4:4 chroma and only the Samsung can be used with your computer, I would like to note that my 10 year old Qualia is used with my 11 year old Sony desktop computer every day to watch online content & web pages & anything else a computer does easily. As you can see with the 2 attachments, although my camera does not do the picture justice and it looks pretty good actually for an older HDTV. If not for the light engine slowly going out I'd keep it. I use a DVI to HDMI adapter with a optical for sound to my receiver. Of course with the newer computers you could easily go HDMI computer to HDMI 4k TV. Nearly all HDTV or 4k UHDTV can be used with any computer via HDMI.
Some connections are better than others of course. If you're a purist though by far the best connection from a computer to a large screen 4K would be Panasonic's AX900 4k & the newer CX850 4k as these models have a displayport input. Honestly I wish all brands had this input by now, unfortunately Panasonic screen sizes max out at 65". If you're a gamer elitist then one would need to consider deeper as your needs & mileage may vary IMO. Panasonic upcoming 4k consumer camcorders even add HDR capability to compliment the newer HDR 4k UHDTV's.
My top 2015 choices in order are, although non of which I can currently afford, saving potentially #4
1) Curved LG OLED 77" - probable release this quarter, but the HRD version is preferred, release date unknown
2) Flat Sharp Beyond 4k UHD 80" - probable release date 3rd quarter 2015
3) Curved Samsung SUHD JS9500 88" - understanding the Samsung S9 85" is 40g the potential price of this is possibly epic - probable release this quarter
4) Flat Sony XBR-75X940c / XBR-85X950B - probable release this quarter
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