I swear by a black & white conversion that I first saw in the magazine Photography Monthly back in May this year and, after reading an article in Light Stalking about such processes, thought I'd post it up on here.
Credit for this process goes to photographer Greg Gorman. It is a lengthy process but I have it set it up as an action in Photoshop. One push of a button (F2 in my case) and the PS goes through all the steps in layers, leaving me in full control over contrast, levels toning etc.
Seeing as it was already publicised, I'm sure I can divulge the details seeing as the creator is credited above... so click 'read more' for the details.