Actually, check out the Empower Email viewer as well (
Empower your BlackBerry with HTML Email Viewer and BES MailBox, I believe).
IMHO, it's better than the current release of BBSmart (I own both) in that it renders emails faster since it doesn't make you wait for images to download (if you have them enabled) to view the email...Empower brings the images down in-line but lets you view the email while they are loading.
Nothing that's available now gives you true HTML, BTW, that is coming, I believe in OS 4.5 combined with server-side updates.