Somewhat related I thought I would post this really nifty technique I discovered for working with photoshop and spriting, take a screenshot of the palette editor, paste it into a new image then crop the image to the palette. You can even save that image for future use if you want.
It doesn't matter if that image is in 8bit or not, the point is it provides a literal artist's palette to pick colors from, and at least in PS7 you dont even have to switch to that image to pick a color or use the eyedropper (hold down ALT and it becomes the color picker, and picking a color from the other image will not switch to it).
There are some people who use the Swatches toolbar but I have never found it useful for anything or how to adapt it quickly like others do, and it just adds another layer of hassle to an already hassle-filled program. Id rather just have it as an image like so.
I discovered this actually when I was doing some ZDoom spriting because I wanted to pick colors that were most likely going to be on the ranges I wanted (rather than an off-red diverting to brown, it has an actual color on the palette to start with)