Besides the rubber floor mat wear, I was also concerned about shoes scratching the paint on the sides of the foot wells. So, I make everyone take off their shoes and wear surgical shoes.
Just joking. I bought a set of cheap floor mats from Wally World and also a couple of Terry cloth bath towels that matched the interior colors. I fold the towels so they cover the paint on the sides and then lay the floor mats on top of the towels. Only about 1-2 inches of towel is exposed on each side. The mat keeps the towel in place and keeps the towel from bunching up under your feet. People don't even notice the towels under the mats unless I point them out to them. When the mats start getting a worn look, I'll toss them and buy a new set. The mat I bought is silver and black and has a sort of metallic, carbon fiber look which goes very well with the interior colors. I've gotten a lot of positive comments on these cheap Wal-Mart floor mats.