These days, the three main resolutions to choose from are HD, 4K (or Ultra HD) and 8K. This refers to the number of pixels carried - and the higher, the better.
You can buy 4K TVs at pretty affordable prices, so we recommend going for it if picture quality is essential to you. It’ll also be future-proof with more and more 4K content delivered via streaming apps like Netflix.
8K is a different proposition, as those who have already leapt are finding that there isn’t much around now to enjoy in the brain-busting resolution. So it’s an expense that may not be justifiable, BUT you may be glad you invested in a few years when 8K movies and TV shows are more common. Technology moves quickly, as we all know.