Gotta love the guys at Gmail; they’ve released an official Gmail notifier. Quote: When you install the Notifier, you will be able to:

• automatically check for new messages every two minutes
• see a snippet of text from up to 30 unread messages
• select a sound to indicate when you have new mail
• make Gmail your default email application

It looks really neat so check it out!

By the way I got 5 invites to give out.. email me if you want one :p