Taupe is such an understated color that I sometimes just forget about it in my collection of berries, hot pinks, and glitters, but boy am I pleasantly surprised everytime I dig it back out. It looks classy and sophisticated because it is a neutral, but more interesting than a plane nude. Best part - ANY skin tone can pull this color off.
There are different shades of taupe, but the one that I personally like is the one that leans more purple. The one pictured below is Forever 21's Love and Beauty nail polish in Taupe (pleasantly surprised by this line and will do a review in the future.) I think this color is discontinued, but there are many dupes on the market currently.