Hey Don,
I like Black & White for situations with little to no colour or where the colours add nothing to the composition the whole impact is light and shade, form/geometry and texture. Whether I shoot B&W in the camera or process the raw file later is unimportant.
In processing, I like converting to grayscale in CameraRaw and then playing with the colour sliders to, say, make the (former) reds stand out or blues darker. It's rather like having a box of coloured filters without having to carry them around, or have to put up with the light loss involved.
I cut my photographic teeth on B&W many moons ago and still enjoy it.