Gmail is my favorite e-mail client, and that is for multiple reasons. It is free, provides a lot of space for your emails storage, offers great spam filters, and many others.
Gmail Manager Extension is a nice application, which allows you to check your e-mail directly from Firefox's toolbar. You can manage multiple accounts and receive new notifications directly to your desktop instead of having to check Gmail all the time.
The program displays account details including unread messages, saved drafts, spam messages, labels with new mail, space used, and new mail snippets. You can specify at what intervals you want to check for Gmail and can customize exactly where you want to place the notifier either in your toolbar and statusbar.
· Manage multiple Gmail accounts.
· Receive new mail notifications.
· Support for Gmail hosted accounts.
· Ability to import/export account preferences.
· Tooltip with account details and new mail snippets.
· One-click access for loading your Gmail account.
· Mailto: links detection.
· Quick mail composes for Gmail accounts.
· Customizable icon placement in the toolbar/statusbar.