Shoot in RAW and then use something like NIK SilverEFX. If you are just using PhotoShop and converting to Monochrome, you are losing a TON of the details. I just did a webinar hosted by NIK with Vincent Versace and was amazed at the differences a piece of software like NIK color effects makes compared to just taking an image and setting the mode to Monochrome (basic just removed Hue and Saturation and throws away more than 1/3rd the detail.
I will also plead ignorant to whether shooting in B&W makes any difference in respect to what I am talking about, but I am making the assumption that it, like other styles, is just a style that is applied to the JPG, hence similar to the Monochrome conversion and losing detail.
really had my eyes opened the other day to just how much detail is in a Black and White image, and why some B&W really stand out and why others are dull. Conversion is really not as straight forward as I originally thought