I love black-on-black-on-black. There are plenty of people who would say that all-black-everything is a bit of a cliché, and a bit of a cop-out style-wise, but I think that those people are missing a trick. All black done really well can be a hundred times more compelling than a rainbow of an outfit.
For me, doing black well means mixing textures for a really tactile ensemble. Autumn and winter are the best time of year for this, because we have so many layering options. I wore my favourite soft black angora sweater with a croc-print leather skirt, opaque tights and my vintage black fur coat, with a splash of leopard print (my favourite neutral) and a little sparkle by way of a metallic-patterned scarf. It's almost my uniform when the seasons change and the weather turns colder.