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

2) AdThwart
Blocks ads on websites. Supports EasyList and many other filter lists.

3) Google Translate
This extension translates entire webpages into a language of your choice with one click. By the Google Translate team.

4) IE Tab
Display web pages using IE in a tab

5) Google Wave Notifier
Displays number of unread Waves.

6) RSS Subscription Extension
Adds one-click subscription to your toolbar.

7) Xmarks Bookmarks Sync
Backup and sync your bookmarks across computers and browsers.

Docs PDF/PowerPoint Viewer
Automatically previews pdfs, powerpoint presentations, and other documents in Google Docs Viewer.

9) AdBlock
AdBlock for Chrome! Removes Facebook ads, Flash animations, and ads from all over the web.

10) Google Quick Scroll
Quick Scroll lets you jump directly to the relevant bits of a Google search result.

For more Extensions Click Here