We're trying to get the attention of someone at Google Gmail who can talk to us about improving the way Gmail handles clean, standard HTML and CSS.
If you are sick of dealing with so many variations in email rendering, the Email Standards Project is for you.
Find out more at Email-Standards.org, and if you are from Gmail, get in touch! [UPDATE: It's working! See http://www.email-standards.org/blog/entry/gmail-appeal-update-we-have-contact/