There are 3 separate aspects:

1. Color warmth--in Kelvin. I think 3000 is perfect. Not too warm and yellow and not the surgical suite/interrogation chamber look.

2. Color accuracy measured by the CRI (color rendering index). 100 is perfect fidelity to the true color. Lower CRI gives sick green tones. Make sure the CRI >90 so the colors are true.

3. Brightness is measured in lumens. For LED strips, look at the lumens/foot. These range widely by product with a good range being probably 125 to 350 lumens per foot. More lumens is brighter. With a dimmer you can go brighter as you can always turn it down.

4. Not mentioned but desirably is "dim to warm"--those are available in some fixtures/bulbs but at a premium price. In LED strips I have seen "tunable" white so that you can create different moods. Still pricey at this time but would be nice for the option of romantic candlelight glow all the way to bright and white.

I love my 3000k lights. As islandgarden said, not perceptibly yellow nor discount store cold bluish. The ones on dimmers do go more yellow as they dim, which might be a brand specific quirk, but I rarely dim them.

Many big box store lighting areas will have a display with the different K's set up so that you can compare their color, and also hold items like color swatches under each so that you can see the effect each one has on the color.

My undercabinet lighting is 2700K. While I do like them as they provide warmth with the dark brown cabinets and white quartz, I think I'll switch out to 3000K for a bit brighter white color. For my kitchen, I wouldn't go higher than 3000K.

My under cabinet lights allow you to choose 3 different color settings. 2700K, 3000K and 4000K. 2700 was too yellow and 4000K was to blue. 3000K was what we liked best.

This is great information, thank you all for your wonderful feedback. It is very much appreciated :)