Postbox is an invaluable tool for email hoarders. It's a downloadable desktop application that focuses on ways to search and organise your messages. It's based on the same code as Mozilla Thunderbird, which means it's light and fast, but you'll find it far easier to locate messages using Postbox.'It has an amazing ability to sniff out every piece of mail you've ever sent, received or begun to compose.

A Picasa-style thumbnail preview pane lets you preview attachments, saving you the hassle of looking through lists of randomly named temp files.