I use RoundCube, and I'm very happy with it so far. It has a very active developer base, and it offers the closest thing to an email client experience. I'm currently working on an "Outlook" theme for it, which should be done soon.

My mail server stack looks like:

Linode + Postfix + Dovecot (w/mySQL & imap) + RoundCube + SpamAssassin + managesieve.

With this setup, I get more powerful mail filters than Gmail, a better webmail client than most ISPs, and spam controls that I can access directly from my webmail client.

It's not the easiest setup to pull off, though. I'll need to roll out a second one of these before long, and I'll try to write it up next time.

EDIT: Or for $5/month/domain (the same deal I give my clients), I'll give anyone unlimited domain email hosting, unlimited accounts, (practically) unlimited storage.

It would be great if you created a Linode StackScript. This would allow anyone to replicate your configuration on their own Linode easily.

OK. I'll think about that -- my desire to "share and share alike" is struggling a bit with my desire to differentiate from other mail hosting services.

http://squirrelmail.org/ is out there. Can't personally recommend, since I've used gmail exclusively since I got an invite, and desktop mail apps (plus hotmail) before that. My college used squirrelmail before they switched to http://www.horde.org/webmail/.

Compared to the GMail UI, SquirrelMail is pretty terrible.

Yeah it's REALLY bad. Funny thing is, and I don't know if this is store-specific or what but as an Apple employee working at the retail store, I got access to all of my email thru squirrelmail. You could only hit it from behind their firewall, but it's http://webmail.apple.com (it will fwd to https://webmail.apple.com/src/login.php if you cancel out of the login prompt, which for anyone who's used squirrelmail, is the standard login page)

Of course I was also given a mobileme account (which uses a pretty slick desktop-like web UI for mail) but I was shocked that they didn't do like a Google-Apps style rebrand of MobileMe email for their own @apple.com accounts. Pretty sad if you ask me.

Already mentioned by sucuri2 in another thread, but roundcube (http://roundcube.net/) looks much more attractive. Still not GMail, but much nicer than squirrelmail.

If you pull down devel-threads from svn, add a couple of plugins, and tweak a few things, RoundCube IMO actually gets better than Gmail.

Interesting. I've liked Roundcube enough to use as a backup way to access mail, but I've never looked at the plugins.

What are some of the plugins that you find useful?

The spamassassin plugin lets you control your spam settings from your webmail account.

I also have managesieve installed, and there's a plugin for it too, so with imap, inbound email gets automatically sorted into folders for me, and I can control that from RoundCube. The filtering is actually way more powerful than anything Gmail can do (last time I checked).

Those are the two "must-haves" IMO.

I agree, it used to use frames, which was rather annoying. But if you don't need too many features, it works.

I've been really happy with Claros Mail: http://www.claros.org/web/showProduct.do?id=1

Way nicer than SquirrelMail.

postfix + squrrelmail

there's also this - http://lmgtfy.com/?q=open-source+webmail

I upvoted you because you have a really cool link up there.

-4 for this?!! what a bunch of pussies.