In the words of Scott Kelby, taken from his book, "Lightroom 2: book for digital photographers":
I don't know many photographers who don't just love black and white. Well, actually the color black. You see, once you become a serious photographer, you want to sell your prints. Of course, once that happens once or twice, you're no longer satisfied with what you wold your first prints for, so now you have to find a way ot charge more. But here's the catch: you can't just sell the same prints and charge more, right? You'd have to shoot new stuff, better stuff, in fact, better stuff then you can actually shoot, which is tough because in reality you can only shoot as good as you can shoot. So, what's going to make up for your lack of talent and vision? Black clothing. You need a black shirt, pants, socks, coat, shoes, etc. Black clothing on a photographer is like magic because that tells the wrold you're not just a photographer, you're an artist and obviously mourning something deep inside your soul. Perhaps an emotional loss, but you're so tortured by it that you can't talk about it. The only way to express your inner angst is through your "art," which is now worth a whole lot more because you're no longer some schmuck with a camera trying to make a buck, you're a deep, mysterious artist they could never understand. This makes your irresistible to people who love buying the work of tortured artists (which is just about everybody). So now you're living in a luxury apartment on the Upper East Side and you've decorated it al in just one color -white. Why white? Because you needed to make a personal statement about monochromaticity, corporate plundering, and man's inhumanity to man. That, and you're really sick of black.