Yeah, I just did the whole Print Screen thing....
I have been messing around with my own chapter quite a bit recently and I have found the most effective method, for me anyhow, is just to go for one primary colour and one secondary colour with separate metallics. Some characters can have swap round the two colours to make them stand out, and a third colour (normally white or black) can be used as well.
I'm sure everyone else is anticipating some pictures of these camo marines!