gradient mapping - although i think that is obvious from Tom's post... tonal control is insane! (plus you dont have to stretch things after using curves to get the right contrasts).  I dont think it is on that tutorial either...

Just play around with the sliders with the preview button selected and see what happens (oh and remember you can add more sliders in there to get more control and the hollow diamond is the midway point marker - move that around and... well you will see)

edit - i realise that this method doesnt allow for changes in specific colour based tonal ranges but just click off the monotone check box on your final choice in the channel mixer window and see if the image you just created is actually "real"... chances are it is a completely weird mix of colours.  That is why i think the channel mixer - which works on mapping the colour to it's "equivalent" greyscale value is more "real" for the eye to accept and thus makes for a nicer B&W... just my opinion tho :)

"In every colour, there's the light.
In every stone sleeps a crystal.
Remember the Shaman, when he used to say:
Man is the dream of the Dolphin"

Rich Meadows Photography