Shooting in black & white

Definitely take all photos in colour. The reason being is the camera's black and white mode just converts all pixel on the image to their brightness values.

If you have the colour information then in photoshop, lightroom, or pretty much every decent image editing program you are able to choose how the colour information manipulates the brightness.

For instance a scene with a red car against the blue sky background would look horrible black and white. But if you take the photo in colour, convert to black and white by using only the red channel which simulates a #25A filter, then the car goes white and the sky goes black making the photo much more dynamic.

Thanks.
I'm new to photoshop and still trying to work things out :)