I really like the lighting and contrast of the bowl.
I"m not sure everyone will 'get' that this is a pipe. It took me a second to figure out what it is. I'd be interested to see it shot landscape instead of portrait and perhaps be able to see inside the pipe bowl. With landscape orientation I might have tried placing the pipe diagonally as well.
pretty lame subject... althought the ligh is good, good details... you should maybe had shown some more of the black background, I also whould have liked it from another angle... - I hope I'm not to hars, one learns from what one is told ;)
Its a very nice photograph, with great texture on that object. I don't really think the negative space has much of a role in this, but that doesn't bother me. 6