For all the roofs I’ve replaced in my remodeling career–which have been asphalt shingles–I haven’t had much influence with my customers over the color they selected, however, I think it’s an enormously important choice for what I consider to be one of–if not the–biggest style elements of your house. I guess I’m kind of surprised I didn’t get a “We chose black, what do you think?” kind of phone call.
Anyway, what I’ve done (like most contractors I’d assume) is provided customers with the sample board from the roofing supply house. Customers look it over for a few days and then call me with a color.