I'd think that trying to use the LCD display on a digital as a color meter would be rather misleading, as well as laborious. The display just isn't accurate enough, and most economical digitals lack sufficient white-balance control to tweak the image's color balance sufficiently.
Getting back to my original "For people, products, or backgrounds" question, I think the choice of lighting gels depends on the objective. I'd see the spread of objectives as:
1. color correction - i.e. balancing the light to the sensitivity range of the film,
2. color enhancement - e.g. slight warming or cooling skin tones for an artistic objective,
3. color drama - e.g. adding a splash of color, or perhaps several, to give the image more visual impact, and
4. background color adjustment - gelling the background differently than the light on the subject, again for artistic and/or visual-impact purposes.
When doing product work, for example, there may be specific objectives for background color based on psychological impact of various colors, perhaps combined with the need to match, compliment, or contrast with logo colors, and so forth. Additionally, the relative intensity of background lights will vary the final color rendition. Thus, choices (and, lighting levels) can become rather complex.
Helen's "standard" gel kit shows a wide range of objectives and on-site flexibility, I think.
I think I've posted this image here before, but it makes a good example. The background was a Thunder Gray seamless paper. The objective was to gel the background, and control the light fall-off to produce a Tequila-sunrise sort of effect that was complimentary to the bright yellow head scarf.