cgardner
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Most often WB problems aren't the method for setting the WB but rather the fact the lighting is mixed. That's nearly always the case indoors when flash is used for color photography.
In mixed light the most effective solution is to gel the flash to match the ambient to the two match more or less seamlessly. Perceptually we key more off what is in the foreground and more on the tone of faces and objects of known color than anything else. So even when I gell my flash I set custom WB off a gray card, then shoot another one with a color target on it after setting WB as confirmation / reference when editing.
Setting the Custom WB based on the gelled flash, not the ambient background ensures that the faces in the foreground the flash is illuminating are rendered neutral. Starting from neutral makes it easier to make decisions about tweeking the WB for effect when editing. Custom WB doesn't affect RAW capture, but it will make the previews on camera neutral and closer to what will be seen in the RAW editor when the file is first opened.
When I can't do custom WB I pick the nearest pre-set and try to put a gray card in a test shot. That allows me to correct the shot with the card with the eye dropper and then copy the adjusted WB settings to the other files. If I can't put a card in a test shot then I just find a file with some neutral gray value, click correct on it, then use the settings from that file to batch adjust the others.
The goal isn't "perfect" color, but simply to have consistent WB shot-to-shot. For that reason I never use AWB which recomputes WB for each shot based on the brightest non-specular highlights in it. AWB works on the assumption the brightest highlights are in fact white. It works OK when the there is a white shirt or wall in the photo, but not so well if the brightest area is not white.
WhiBal makes a big deal about how perfectly neutral the cards are, but in practical terms that isn't critical because the best looking color balance in photo perceptually is seldom a clinically pure neutral balance. Any reasonably neutral target will serve the purpose of providing a consistent baseline for color management. The goal is consistency, not neutrality.
Portraits look better perceptually when they are a bit warmer than neutral. Color also conveys mood and triggers emotional reaction. If you want the viewer to shiver (and smile an the same time) when they see a naked woman lying a snow drift you'll want to bias the WB on the photo towards the cool side. She might actually be shot lying in fake snow in a studio and shot holding a gray card for with perfectly neutral WB out of the camera, with the decision how to bias the color cooler made later when adjusting the RAW file. RAW makes color like clay, able to be molded into whatever form best conveys the desired subliminal message in the photo.
Film makers are masters at this. Last light I saw a mundane Prilosec (antacid) commerical on TV and was impressed with how the production designer or cinematographer had match the clothing and WB of the lighting in background to give everything a cool, moody, vibe; how you'd feel before taking it, then cut the after scene with warm colors and normal WB.
We need to look beyond the technical to see the broader perceptual goal - how we want the viewer to react. Being able to do that at will is a matter of knowing how to apply the technology effectively. In the case of shooting WB we simply need to keep the WB consistent shot-to-shot so it is possible to batch correct the WB in all the files the same way with a simple copy/paste of WB metadata in the RAW files. Trying to make it any more complicated isn't a bad thing if it makes one feel the color is "better", but is more work to achieve same end: color which fits the context of the message and looks real. That is a perceptual judgement that can only be made by eye 
Chuck
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