A repost from the Xbox thread - the two 'best' TV's you can currently purchase for around £1k (at 55") Both are full UHD Premium TV's - meaning they are capable of delivering HDR to the 'minimum' standards if not better. Any TV that does not meet these specs will not be delivering HDR to the 'MINIMUM' standards but may just enable you to 'view' HDR content - in a similar principal to 'downsampling' a 4k image so you can view it on a 1080p screen. It may be 'better' than SDR in some cases, in others it can actually look worse (much darker) but to avoid any disappointment, its worth spending the extra to get at least the minimum standard of HDR.
55"KS7000
UE55KS7000 - Winner of What Hifi's best TV of 2016, UHD Premium, 4 full bandwidth HDMI's and better in some key areas than the Q7F QLED - under £1k
Or for £100 (£1099) more,
SAMSUNG UE55KS8000 Smart 4k Ultra HD HDR 55" LED TV the 55" KS8000 (only 1 left) and more comparable to the Q9F QLED - again 4 full bandwidth HDMI's, UHD Premium certified
Both great gaming HDR TV's too - no 3D or Dolby Vision - but not needed for gaming on the current consoles and both a great match for the Xbox One X, PS4 Pro. I have the 8000 and its fantastic! The 7000 was most gamers choice last year with the PS4 Pro and the XB1s.
In many ways, HDR is the more important upgrade than resolution - it will have more impact - especially on a 55" screen at normal viewing distances. Compromising on HDR is like buying a 720p HD TV because its 'cheap' and 1080p content can still be watched. The Xbox X will not only offer games in HDR, but also Blurays, Netflix/Amazon maybe even youtube too. If you don't buy a HDR TV, or one that's downgrading it to almost SDR standards, you are missing out on the more impacting visuals that gaming and movies can offer.
I appreciate its not cheap to get a 'decent' HDR TV but its worth spending the extra, make do with whatever you have or buy the TV now and wait until you save enough to upgrade to the 'X' - especially if you own a Slim as you can still benefit from the HDR and then upgrade to the X to get the resolution. At least if you have the TV, it can benefit you in the meantime as the X isn't out until Nov.