Since my domain was for my blog before I started the business, my business is actually a subsite of the domain. So I created a
VA@domainname.com for my business, so mail for the business doesn't get mixed up with mail from my blog (which can be extensive). Really, any descriptor that is good for you works. Most people don't see past the name of the link.
The idea of having multiple e-mail addresses for different pages and marketing campaigns is a good one. Helps you see what marketing is most effective for your business.