I have an HDS EDC XR and from what I understand they all have a led that tends toward the blue (still very white though). When I first became infected with an LED fascination, the ghostly blueish cast of LEDs was part of the appeal. However my tastes have grown up a bit and I now much prefer warmer, more yellow LED's. I'd agree with what Jayflash said about incandescents providing better color rendition in nature and find that LEDs with more yellow are superior to white and cool LEDs in this respect as well. When I take a blueish or white led and light up an area outside and then switch to a decent incandescent it's like adding another dimension to the visibility. They also seem to provide better detail and depth both inside and outside. It is interesting to note that surefire now has a yellow-green led option in the A2 because they've found that the eye works very well with this kind of light. Amber shooter glasses also back the added benefit of the yellowish spectrum to enhance depth and detail. This being said, I think that for my money and taste, the best light would be the standard ultimate, even though I've already got an XR.
If ledheads became more interested in scrutinizing the image of what is illuminated rather than the illumination, the oft maligned yellowish or greenish leds would be appreciated at least as much as pure "white"