Gmail Notifier Plus
Gmail Notifier Plus is a small, fun application to monitor multiple Gmail and Google Apps Mail accounts from a single, compact point. With it's slick, native look, GNP notifies you in a variety of ways of your new mail, and allows you to quickly nagivate older new mail without opening a browser.
Super Amazing Screenshots
More screenshots here: Screenshots
Unless otherwise stated, the code here is licensed under the MIT license. Have at it!