I have a client who is requesting an HTML-formatted email to promote an event. Her reasoning is fair enough: She wants a striking layout, attractive graphics, and she doesn't want her recipients to have to click on anything in order to see all of the information.
I've never sent an HTML-formatted email because it is sort of demonized, and not without reason. Even Gmail treats HTML/included images as a sort of contraband. I'd usually link to a website, but in this case, there isn't one.
Since it's probable the client will insist, do you have any best-practice tips, or examples of good methods? Or, alternatively, a good alternative method?