It depends on what you feel is best for you.
HD ( 1080p, for example) is always reasonable -- far better than the "old" ways, of course, and far more efficient.
But Ultra HD ( 4k) is easier on the eyes, especially in a large format. Most "smart" TVs are at this resolution currently, but SUHD (8k) is coming in fast and furious. It is almost slow ISO quality in the pictures, compared to fast ISO quality for HD format.
But, overall, the bigger the screen, the better going to SUHD (8k) -- close to a cinematic experience!