Mailplane is a great Gmail desktop client for the Mac. It allows you to use Gmail the way it is intended to. I have been using Mac's Mail.app recently, because I grew tired of Gmail notifier not telling me when I got new messages. Mailplane will change the way I check my e-mail on the Mac forever.
The application allows you to have your Gmail account on your desktop at all times. You can use it just as if you were on the Gmail website, but it has some great features that can save you time and make your experience way better. There's so much to say about this app that I don't think I will be able to say it all. But I will go over my favorite features.
The first thing that comes to mind is Growl support. Mailplane will send you notifications and play a sound when you get new e-mail. It seems to be very responsive, and you won't go hours without getting notifications to then suddenly getting 20 all together, like Gmail notifier does. Another great feature is that you can attach files to your mails by simply dragging and dropping files onto the Mailplane app. You can even compress images further with this app. There is also support for Address Book and integration with Chrome, Safari and Firefox to let you compose new messages when you find a Mail:to tag. Users with multiple Gmail accounts will love the Accounts tab, which lets you switch between them automatically, without even having to input passwords each time. All your login information is stored in the keychain securely.
All in all, Mailplane is a winner and a must-have for any Gmail user.
Messaging application designed for Mac.
Mia for Gmail (was Notifier Pro for Gmail) is a desktop Gmail client which sits politely in your menu bar.
Standalone browser for the Gmail website.
An application that makes possible for you to manage your Google account.
Free Mac OSX Gmail nofiticator.