-i1DisplayPro if you are going to use now or in the near future a monitor with HW calibration. If you are going to measure a huge measurement of patches for video LUT3D, it’s speed is worthly of the price.
-Colormunki Display if above conditions do not apply. It’s accurate and it’s cheaper but it’s slower and you cannot use it with most/all HW calibration solutions.
-one of the above colorimeters + one Xrite spectrophotometer (i1Studio or better an i1Pro2) for measuring most backlights accurately. Take a reference (spectral or coordinates) with the spectrophotometer, the measure with colorimeter corrected with that reference. Not all software supports this “spectrophotometer-colorimeter matching”. DisplayCAL does.
This is 3x-10x more expensive than some of the previous solutions.