yourbusiness@bigpond.com and yourcompany@hotmail.com are examples of common business email addresses. But these types of email addresses send a negative message about the value of email within your business. Hotmail, Gmail and Yahoo emails are free, and Bigpond and Internode addresses are provided free with an internet connection. Customers get the sense that you don’t see email as a valuable tool, that you only have an email address because you have to and that the email may not be checked regularly.  If this is the first impression a customer has of your business, it will impact their decision to make contact with you.
Email enquiry from a potential customer need close attention. It is very likely that the phone number and even your street address were right next to it, so a conscious decision has been made to use email, implying that this is their preferred method of communication. A reply two days later requesting the customer telephone you instead implies that your business can’t be bothered thinking about the enquiry. 
Instead you should reply promptly, endeavour to answer all the questions posed in the email, request any clarification required by email, and if phone communication is necessary, ask if it would be okay for you to call the customer. If the information the customer needs is not readily available, a reply thanking them for their contact and advising when the answer will be forthcoming will go a long way to preventing them from contacting a competitor in the meantime.

“ Customers get the sense that you don’t see email as a valuable tool, that you only have an email address because you have to. ”
A speedy response is always appreciated by the customer, but is not always possible if you don’t spend the entire work day in front of your computer. Smart phones such as BlackBerry, iPhone, Android and Windows Mobile devices will download email on the go, allowing you to reply from just about anywhere.  This can make communication far easier while on the road, providing the illusion of size for smaller businesses, and demonstrating to customers that their enquiry is important to you. 
Of course all of your communications, including phone and email, are coloured by the individual character of your business, so I’m wondering, how does your business email communication differ from the methods outlined above?