10 best chrome extension for better Gmail experience

Gmail Offline beta is a Gmail app built to support offline access, allowing mail to be read, responded to, searched and archived without network access. After first start-up, Gmail Offline will automatically synchronize messages and queued actions anytime Chrome is running and an Internet connection is available.
To start Offline Gmail after installing, open a new tab in Chrome; In the new tab pane you will see a Gmail Offline Icon. Click on the icon, and Offline Gmail will load.

Gmail + LaTeX = GmailTeX. Allows one to use LaTeX (a method for typesetting mathematical formulas) with Gmail.

Displays the number of unread messages in your Google Mail inbox. You can also click the button to open your inbox.

Boomerang allows you to schedule messages to be sent or returned at a later date. Write a message now, send it whenever, even if you're not online. Track messages to make sure you hear back, and schedule reminders right inside Gmail.

Makes Gmail your default email application and provides a button to compose a Gmail message to quickly share a link via email.  This extension will open a Compose window in Gmail when you click any email address on a webpage.

It also provides a button that will create a Gmail message when clicked, using the page title as the subject and selected page text and link address as the message. For setting the domain name of your "Google Apps for your domain" account, click Options

6) Better Gmail
Better Gmail will help you remove unwanted features in gmail such as chat, invite friend, ads...It also checks for new messages and notify you.But it doesn't work with the new Gmail UI currently. Working on it. Patience
Save those pesky Gmail attachments directly to Google Docs from the attachment list itself with a newly added Save To Docs link.

Add contact photos to the mail list and into the mail body. Configurable insertion and position.

Displays new emails and the sender's contact photo, get desktop notifications or even listen, read or delete them without opening a mail.

Icons in new Gmail themes are all black. This extension just replaced them with color ones for a better user experience.