I use these extensions for Chrome:

• Adblock Plus (Beta)
  Ads were yesterday! The successful extension Adblock Plus is now available for Google Chrome.
• Firebug Lite for Google Chrome
  Firebug Lite for Google Chrome, supported by the Firebug Working Group.
• Google Chrome to Phone Extension
  Google Chrome to Phone Extension enables you to send links and other information from Chrome to your Android device.
• LastPass
  LastPass is a free password manager and form filler. LastPass is also available for Firefox, Internet Explorer and Safari.
• New Tab Blank
  When you open a new tab, a blank page opens instead of the new tab page.
• Python Search
  Adds support to the omnibox to search Python reference documentation.
• Reddit Enhancement Suite
  Reddit Enhancement Suite - a group of enhancements for browsing Reddit
• Smooth Gestures
  Mouse Gestures! Quickly and easily navigate webpages using the mouse or keyboard.
• Stylish
  Restyle the web with Stylish, a user styles manager. Stylish lets you easily install themes and skins for Google, Facebook, YouTube, Orkut, and many, many other sites.
• Type-ahead-find
  Find text or links as you type
• Xmarks Bookmark Sync
  Backup and sync your bookmarks, passwords and open tabs across computers and browsers. Xmarks is also available for Firefox, Safari and IE.
• Yet Another Drag and Go
  Drag URL to open at Back/Front, Before/After; Drag text to 4 directions to search by using different search-engines.