I have a hard time doing it, just because I'm tall and lanky and a solid black column looks even more emaciated (but I eat all the time, seriously!). I find myself using black as a really reliable color for outerwear, just because I can throw on some color underneath without it looking like I'm a giant, talking crayon.
I do have a tendency to rely upon black shoes, though (suede loafers, Chucks, Vans Authentic, and Puma Tatau Lo), which is something that I've really got to work on.
For people who can wear all black, there are great labels out there that know how to do black: Ann Demeulemeester, Rick Owens, Raf Simons, Number(N)ine. And I absolutely j'adore what the Viridi-Anne folks pull out. So I am certainly jealous about people who get to pull that off.