Windows/Mac: Postbox, the attachment-savvy desktop email manager we toured during its beta, hit an official 1.0 release. You can try the finished product free for 30 days, or buy a single-user licence for $US39.95.
Postbox has been busy adding features, functionality and search refinements with frequent beta releases. Just two months ago, they loaded in add-on support, and now that list of supported extensions includes the killer Lightning and Provider for Google Calendar combo, support for Growl notifications, the MozBackup service, optimisation utilities, and much more. As Web Worker Daily points out, there's also a bunch of new Gmail-like search operators to work with, in the style of from:jason.
Windows and Mac users can give Postbox 1.0 a look for 30 days free before the software asks for a registration, and there are family pack and lifetime registration options available. Tell us if you're digging Postbox, or have long ago left desktop email behind, in the comments.