I always choose "warm white" (2700 K). I much prefer the warm relaxing light quality, similar to incandescent light. Anything like 5000 K or daylight, I find almost painful to experience. It's cold, clinical, industrial, harsh.
Another important thing is, whatever color temperature you choose, make sure it has a good CRI, 90+ or 95+, for good color rendition. That is also really important for eye comfort.