MailBar!

Postbox is an email application that helps you organize your work life and get stuff done.

Kiwi for Gmail (formerly Gmail for Mac) turns Gmail into a full-powered desktop email client. No one wants to use Gmail in the browser on their phone, and we felt they shouldn't have to on Mac or Windows either.

POP Peeper is an email notifier that runs in your Windows task bar and alerts you when you have new email on your POP3, IMAP (with IDLE support), Hotmail\MSN\LiveMail, Yahoo, GMail, Mail.com, MyWay, Excite, iWon, Lycos.com, RediffMail, Juno and NetZero accounts. IMAP supports allows you to access AOL, AIM, Netscape and other services. Send mail directly from POP Peeper and use the address book to email your frequently used contacts. POP Peeper allows you to view messages using HTML or you can choose to safely view all messages in rich or plain text. »

Unibox is a people centric email client that organizes your messages by person. It avoids having email like a to-do list.

Mia is a native Gmail application on your Mac's menu bar!

You like threaded conversations, googling your inbox, and you prefer labels over folders. You really love Gmail.

Gmail Notifier Pro is a Windows application capable of checking multiple Gmail accounts for new mail and display notifications.

Secure check new Gmail.

Gmail Peeper is a free Gmail notifier program which provides an attractive and simple way to check for new mail messages without opening your browser!

GMDesk is an application that lets you run Gmail, Google Calendar, Google Docs and Google Maps as a stand-alone application to do all your mail handling, calendar event reading etc with. No need to open it up in a web browser, or have it clutter your workspace.

Gmail Notifr is written in RubyCocoa and has these features:

MailTab for Gmail is the ideal app for instantly accessing your Gmail account without having to open your web browser. Download it for free and benefit from visual and audio mail notifications, quick access to your inbox and the ability to respond to mails at lightning speed.

This is a Firefox extension that allows you to manage multiple Gmail accounts and receive new mail notifications. It displays account details, including unread messages, saved drafts, spam messages, labels with new mail, space used, and new mail snippets.