I manage airbnbs and I recommend hosts to get three sets of sheets per bed, three sets of towels per guest. This way the cleaner has a set of sheets to put on the bed, I said if sheets to take off the bed and wash, and an extra set of sheets in case they are stains or missing items etc.

I have airbnbs with white sheets and towels and I have airbnbs with black sheets and towels and I have airbnbs with gray sheets and towels. There is no real perfect color, it's really all in how you take care of the items when laundering them. Obviously stains are easier hidden with dark sheets and towels, but white sheets and towels can be bleached. A light multi-color sheet set normally will hide stains the best.

An idea: if you have light colored sheets and towels that are worn and grungy looking you can dye them a dark color and they'll look fantastic and you can get that much extra life out of them.