If you find yourself using Amazon SES for sending outgoing emails in a PHP web app, getting everything set up is much simpler than it may seem. In my case, this was on an AWS Linux image, but it will work on any Fedora/CentOS AMI.
Postbox is a new cross-platform for both Mac and Windows that promises to finally deliver what so many email clients before it have promised. Advanced functionality like Outlook, without, well, Outlook. More native features and intuitive interface than Thunderbird. Conversation threading and tagging like Gmail, without the inelegant webmail interface. Can it be so? Well, mostly, yeah.