Seeing red

December's 'Business Life' has an interesting feature on the use of colour in negotiation scenarios: 

"The colour of your office walls could influence how good you are at negotiating. A series of studies examined negotiation behaviours in various settings, including online auction sites. In auctions the colour red can lead to more aggressive bidding and people can end up paying more. In a negotiation the person competes against the seller and red influences them to make lower offers. 

So if buyers are competing for your services, the primary colour used on websites and marketing materials should be red, but when trying to avoid a buyer's aggressive instinct, you should use a more neutral, calming colour."