If you're tired of Microsoft Outlook, or just want something new from your desktop email client, you could give Postbox a whirl. At the moment it's in Beta, but it works well and has some interesting features.
Postbox is based on Thunderbird, and this is visually obvious the moment you run the program. Installation and setup is easy, and as you'd expect you can set up multiple email accounts. There is an excellent search engine which requires your inbox to be indexed for rapid results. If you have thousands of emails, the first indexing might take a little while, but after that it's not something you'll notice.
One unusual feature in Postbox is the tabs. There are contacts, images and attachments tags. The images tag, for example, will show you all the images from your email, and this works for contacts and attachments too. These can then easily be accessed and added when composing email, which turns your inbox into a useful active database. They are also fully search-able, so finding that picture of the cute kitten that so and so sent you becomes much easier.
Highlighting any text and right clicking gives you a range of useful tools, from Google and Amazon searches to listing on social media sites. The former is useful, but the latter feels tacked on and not fully implemented yet. You can, for example, post highlighted text to Twitter and Facebook (as a status update), if you allow Postbox to login to those services. However, these are currently very basic, and unlike some social media clients, there is no way to add your Facebook news feeds etc. You can also add RSS feeds, although as a reader Postbox is still a little basic.
While a little beta-rough around the edges, Postbox is still a very able email client with some promising new features.
