Yesterday a friend pointed me in the direction of Vibealicious’ Notify, a really neat clean alternative to Googles own Notifier. The application 
is for Mac users only, and all you need is a Gmail account.
Notify works in a very similar way to the official Google Notifier, but has some added touches that sets it apart for me. It has Growl notifications built in, along with support for multiple accounts via a tab interface, and an overall better user experience for quickly getting a glance at whats in your inbox. You can set the the app to check for new mail at a number of set intervals, and I have mine set to check every minute.
Of course a lot of Mac users will opt to use the Apple app ‘Mail’, but for those that just can’t break the habit of using Gmail on the web then Notify is a slick solution to knowing when you’ve got mail. If you give it a go, be sure to let me know your thoughts.