and photograph color in RAW. I overexpose enough to get a decent contrast but not blow the highlights. A spot meter helps with this. In post I convert the file in various ways, sometimes using the resident software for my Canon, or with PSCS channel mixer, or some actions I find useful. It just depends on what I want the photo to look like. Sometimes I do two versions of the photo in post and stitch the layers to make a photo that I "saw" when I looked through the viewfinder.
This photo started out as a color photo with two versions processed for the foreground and the background and then later I converted it with channel mixer in PSCS
http://www.pbase.com/jypsee/image/37516158
here's the color version
http://www.pbase.com/jypsee/image/47290821
here's an all stitched photo that I saw in my head; it's various photos layered and stitched/painted in photoshop
http://www.pbase.com/jypsee/image/71093529
Here's a photo made in color and converted using only the software that came with my camera
http://www.pbase.com/jypsee/image/94238556
I also use lots of filters, especially here in Florida where the sun is much brighter than in the north (USA). I often use a ND grad on clouds to keep them information rich. If I can use a polarizer for the whole scene, then I use that. A polarizer affects the sky in ways that may or may not contribute to what I want in the photo; and it's important to keep the polarizer located at a ninety degree angle to the sun and to remember that if you plan to stitch a pano with your photos that the polarizer will affect your sky as you move across the horizon.
Well placed polarizer
http://www.pbase.com/image/43264522
poorly stitched pano illustrating the polarizer problem
http://www.pbase.com/jypsee/image/47863184/large
sometimes you just do it anyway to get the scene and let the viewer sort out the issues...
My decisions are mostly driven by what I want the photo to look like; I have a photo in my head before I lift the camera from my bag. Here's a photo I made in the brutal mid day sun. I wanted to retain the clouds and keep the foreground properly exposed. It took a polarizer for the clouds and a ND grad for the foreground to keep all the elements properly exposed.
http://www.pbase.com/jypsee/image/87750786
a favorite filter of mine is a Singh-Ray blue and gold polarizer; here's a photo that, though not BW, shows the potential for keeping everything exposed in a way that I had in my mind
http://www.pbase.com/jypsee/image/75174491
more examples of the Singh-Ray BG polarizer and how it can make the photo useful for BW
http://www.pbase.com/jypsee/image/63723574
Mainly, use color and RAW as your starting point and go from there. It's all a matter of what you see and how you want to get it for the final photograph. Experimenting helps you learn a whole lot.