I mentioned a while back that I had purchased a Robin Myers grey card. Here is an example of a RAW conversion using the 'As Shot' white balance obtained with the card. I'm really happy with the colors on this. Without the card I was a long way off.
In this case I shot my Canon 580EX through a shoot through umbrella located at camera left. In behind I used my reflector still in the black/silver case with the black side facing the camera. With the flash diffused, but so close to the background, I had to reduce the black a bit to get the background not looking slightly grey. It is a bit of a cliche shot, but I'm developing skills here!