A Creative Communications Agency

Think Vitamin has a decent look at HTML email issues. They don't quite go to the lengths we do here, but it is one of the better write ups I've come across and does a decent job of at least touching on the important points.

HTML email - you either love it or you hate it. Some love the simplicity of text-only emails, while others praise the flexibility and good looks of HTML. But it doesn’t really matter whether you love it or hate it because sooner or later a client will ask you to design one of those ‘pretty looking email thingies’ for their own customers, and then what do you do?

Link: HTML Emails - Taming the Beast (Via Vitamin)