I’ve been using Mozilla Firebird as my main browser for the past couple of weeks, and at this point there’s probably no going back to plain old Mozilla. I had still been using Mozilla as my IMAP client, though, until a couple of people clued me into the fact that Mozilla Thunderbird has alpha builds available that are at roughly the same level of maturity as Firebird. I downloaded it earlier and I’m trying it out for email. I have to say that I like it pretty well, and once you install it, mailto links start working in Firebird as well. If I run into any catastrophic problems, I’ll report them.