The 1.0 version of Mozilla Thunderbird is out as of yesterday. It’s officially suitable for public consumption now, though we’ve known this for quite some time now. In addition to having the great advantage of not being Outlook Express, Thunderbird has an excellent junkmail filter, thorough message rule capabilities, and a neat new feature (introduced in version 0.9) that allows for grouping messages by date, sender, subject, etc. in collapsable trees. Go check it out, download it, and ditch your old mail client.