So I'm working on this site while I scan in a bunch of negatives so that I can have digital copies of my black and white photos-- which is nice because photo paper is super expensive.
I really like a lot of my black and white work, because it takes a different sort of magic to make black and white images work. With color, even if the image is poorly composed, or sort of uninteresting, beautiful colors could grab a viewer's attention. It's like wow, those colors are so beautiful, surely this is a beautiful images.
However, in a black and white, there's no hope of color to rely. It's much more subtle: you need to have good contrast, a good range between black and white, and even then your image still needs to be well composed.
Also, while you shouldn't rely on it...black and white does tend to add a touch of seriousness to the image.