If you access your email in a browser, you'll love Notify. Notify is an awesome email notifier for Mac OS X. It fits seamlessly into your menubar, only vying for your attention when you have new mail. Notify supports mutliple accounts, including Gmail/Google Apps, MobileMe, and Rackspace Email. All in a beautiful interface.

Features:

Mail Accounts Notify supports Gmail, MobileMe, and more. All in a beautiful tabbed interface.

Notifications Notify's notifications are easily configurable to meet your needs.

Full Preview Easily preview entire messages right on your desktop, without a mail client.

Mark Read, Delete, Move Mark messages as read, delete them, or move them - quickly and easily.

Send & Reply Reply to messages and send new ones without needing a full mail client.

Multiple Message Selections
Notify allows you to easily select multiple messages, as you would in any other application.

Mail Client Integration
Notify integrates with your system's default mail client. Set Notify to open a message in your mail client when clicking a Growl notification, or when double clicking a message in the message list.

Non-Blocking Controls
Notify used to block the UI when marking a message as read, or deleting. Now, these things happen in the background, allowing you to continue to move and manage messages without delay.

Preview Window Controls
Controls in the preview window allow you to mark messages read, and delete them from the preview window. We've also added Previous/Next buttons to allow you to more easily navigate the message list.

Move To Functionality
Move messages to any folder within your IMAP account. Hold down option while moving messages to also mark them as read. This allows Gmail users to archive mail.

More Preferences & Other Improvements
These include more check intervals, more options to set click and doubleclick actions, more Growl click options, etc. And of course, we've fixed a ton of bugs.

Limitations: Notify is no longer for sale. Existing users may continue using Notify as long as they please. If you'd like to use Notify anyways, you can download a license here. You'll have to unzip it, then drag it to the unlock window.

Requirements:
OS X 10.5.8 -10.6
Intel