When creating Quotes/Sales orders, user should be able to select the contact whom they are dealing with at a header level for a specific sales order. Companies have multiple contacts placing orders and when you send emails out or call the company for discussing the sales order/quote further, there is no way to know who the contact was who placed the order with you.
We get this request all the time and I know people have customized this on many occasions and this really belongs in the product.
System should initially default this new contact field with the main contact of the account and the user should be able to change it for the specific order/quote.
When emailing the document, the default email address used should use/include this contact.