I've got a partial brick wall in my garage on the driver's side. It's a perfect height for dinging the edge of the door when getting in and out of the (somewhat narrow) garage.
My car is the '07 Plum Mica - a fairly dark color. I just went to the auto parts store and got a 10ft. roll of self-adhesive flexible door edge guard molding. Left out in the sun a few minutes prior to unrolling and sticking on, it has worked great for the past year. My previous car, a 2003 Focus, had the identical product and they held tight after 4+ years on the car.
As for appearance, my car is a fairly dark color and the the moldings simply disappear and are almost invisible. So, if you have one of the darker colors and want the added protection, I'd say go for it. The stuff I got probably cost around $14 or so....