Used to be, "Is HTML or Plain-Text email better?" was a pretty important topic. Back then, there were tons of plain-text die-hards. Nowadays, you don’t hear so much from them anymore. Did they all die off? Did email apps start rendering HTML better? Did they just get tired of complaining? Anyway, ClickZ recently raised the topic again, and everyone seems to agree—who cares? Send Multipart/mime and let the recipient choose. Oh yeah, which is what MailChimp does. Some people don’t know this about the chimp, tho: you can send only plain-text. Or, you can send only HTML. We recommend you send both, of course.
Here’s the link: http://www.clickz.com/experts/em_mkt/em_mkt/article.php/3448841