Postbox was released last year as beta and had received great responses from users. It was the perfect E-mail client with all features you would ever need and an intuitive interface. However, when the product got out of beta, they set a price tag of $39.95 for the mail client.
Now the makers of Postbox have released Postbox Express. Yes, a free version of the Postbox mail client with stripped down features. But if you are just looking for a basic mail client with a great interface, then look no further. Postbox Express is here.
You can see a comparison of Postbox and Postbox express here.
Here is a preview of Postbox Express, fewer features with the same great interface.