Depends on the material and cut of the clothes. Wearing all black simple clothes, such as a wool skirt and a pullover, is rather boring. Not very fresh. But if you wear black clothes with good details and/or interesting shapes, then it is very chic!
I wear a lot of black for every day in Fall/Winter, but I always try to brighten it up with some colourful accessories. Very subtle though, like a scarf and gloves. In Stockholm, everyone wears black in the winter. I thought about this while on the metro yesterday. Everyone, in the part of the carriage where I was sitting, was wearing black. It was very funeral-ish..