Getting Into HTML Formatted EMAIL

We began getting into HTML formatted EMAIL when users began requesting an automated way to retrieve / reset their Login credentials (User ID / Password). So, we now enable them to send themselves an HTML formatted EMAIL containing a temporary hyperlink which enables them to do that.

Now, we're finding many other applications for HTML formatted EMAIL.

However, as we began testing this with various EMAIL clients (GMAIL, Yahoo Mail, MS Outlook, iPad, etc.), we discovered that the final formatting was NOT consistent. Vertical spacing and alignment was particularly inconsistent.

After several tests with various HTML tags, we concluded that using HTML Tables with fixed widths yielded the most consistent formatting across clients.

Do you have any tips for supporting HTML formatted EMAIL, and supporting many EMAIL clients?

-Nathan