Options: Clean up user interface (remove ads, footer...) - Make Gmail default email application - Add Gmail desktop notification
Better Gmail will help you remove unwanted features in gmail such as chat, invite friend, ads...It also checks for new messages and notifys you.
Use it to:
Hide ads & people widget.
Hide invite friends field.
Hide web search button.
Hide buttons "New Window, Print all, Expand and Forward"
Relocate contacts and tasks to top navigation
Add attachment icons.
Add row highlight on mouse over.
Open e-mail links with Gmail.