Scott's Gmail Alert

With Scott's Gmail Alert you will be able to monitor your gmail account, get RSS feeds, receive chat messages, check your calendar, get email notifications and even the weather.
This tools is amazing, completely free and good looking.

You can add as many accounts as you want, and monitor them all from one single application. I must mention that this software is completely free and doesn't have any limit in features, but it does have a few limits on how many accounts you are able to monitor. To change this the developer asks for a voluntary registration process on which you have to pay $3.00, which is a symbolic price for the great application you will be getting.

Features:

1. Manage any number of accounts, the registered version has UNLIMITED accounts.
2. Reply and send emails from your desktop, without opening the browser.
3. Fully customizable application, colors, text, sounds, options, size, etc. Very flexible.
4. Able to schedule when you want to receive notifications, this way you won't be bothered at specific times of the day.
5. Several languages are supported.