I do my email using Opera. Opera is fast as a browser and it's convenient to open web links from emails in the same application.
A few days ago, I had an email disaster. I had just switched from internet work to email only to find, much to my horror, that all my current and previously stored emails had disappeared. Somewhat surprisingly, Opera's email client continued to work normally in terms of downloading and manipulating new emails. I had not been backing up the .opera directory....