<p>Are there any good and easy to use options for sending secure email?  Why is this not commonplace?</p>

SMTP has extensions which support encryption which are supported by most vendors. The receiving server is required to have a certificate (not the sender). So configuring your outbound mail relay to insist upon encrypted connections and verify certificates will usually do it.
If you want to encrypt it as far as the end user, S/MIME or GPG are the two main options. S/MIME support is built into mail clients MS Outlook, Thunderbird and some others.
However, there is still a significant problem of certificate management, which is a royal pain in the arse most of the time.