Gdow is a highly configurable Gmail notifier. It can notify you with a classic messsage box, a popup balloon or a transparent animated form.
Here is a list of (some of) its Gmail account management abilities:
1. move mail to trash
2. move mail to archives
3. spam mail
4. unspam mail
5. star mail
6. delete mail for ever
7. see message body
8. reply
9. download attachments
10. empty spams, trash, drafts
11. send rapidly short mails with attachments
12. pick, add and edit contacts (with full details)

Requires Microsoft .NET Framework 2.0.

The license of this software is Freeware, you can free download and free use this email tool software.