Let me start off by saying that it's a pleasure reading email again

Zimbra is a little heavy for my family email, but heck, it kicks the pants off Squirrelmail (yeah, not hard to do, I know). I do have some comments though.
Wants:- Keyboard shortcuts (ala gmail)
- Tab navigation (I saw someone else comment on that too)
- Mailbox refresh interval changable on a per user basis

- Better anti-spam (it does pick the below up if installed, so not the end of the world)
Vipuls Razor
DCC
Pyzor
Blacklist accounts 
- gzip compression - I can't tell if this already happens or not
- quicker access to filter (filter based on current email?)
- When in the filter screen, I get annoyed when changing the condition type wipes out the text field containing the previous text (this is especially annoying in combination to another bug I've unreliably hit that changes my "header" condition to a "from" condition)
- Ability to send email from other accounts (or aliases)
- quota's larger than 2GB - which begs the question, what's the limit w/out quota? is it 2GB also?
Likes:- Dragable folders (omg, I discovered this one entirely by mistake - maybe I should read the manual? heh)
- The whole UI - it's sweet...can't wait to see what happens when external artists decide to start skinning it
- URL preview (however, loading non-encrypted content on an encrypted page is kinda bad form
)
Yeah, I know short list of likes...there's more, just not quite as intuitive. Good job guys, this is an awesome product!
--Bill