Emailing Leads - Proper way to Setup?

How do I have to setup a lead properly in order to be able to easily email leads. Right now we have client for the lead as an 'account' or 'company'. If we do that, nothing shows up when we select 'new email'. Only if the contact is a person and there is a valid email entered.

Would be great if it used the 'Primary Contact' information if we select a company or account as the client for the lead.

If it doesn't work this way, way is there a selection of a 'primary' contact at a client? Whenever is this used?