Most times I just use my conversion software to "develop" the RAW file to JPG format then process it in Photoshop or equivalent (In truth I now mainly use Corell Paintshop Pro as it has everything a photographer needs (maybe not everything a graphic designer needs) and is quicker and easier to use than Photoshop. Such image processing software allows more control such as thru Channel Mixer and a native Corell black and white conversion tool which is very intuitive.
There are also a few freeware plugins that also do a good job of black and white conversion.
Cybia Fotomatic BW plus is one you may wish to try although it only uses presets and therefore is less flexible. But it never the less is pretty good -especially for the price :^)
Another is just called
BW conversion - not sure who makes it but here is a link
http://www.photo-plugins.com/Plugins...version-2.html ) These plugins only support JPG not RAW files. Hence the need to convert first.
Pretty much the only time I do more than use my RAW software to convert to JPG is when a photo needs a lot of effort fix a badly under or over exposed section. This is better done form a RAW file. The rest of the time, the image processing software working on a JPG seems better.