Here are some very useful Google Chrome Security Extensions
I use very little extensions personally, but i do use the AdBlock Plus Beta extension & also the WOT, I have tried other security extensions but I find many of them quite annoying, However here is a useful list for those of you who wish to use them.
Adblock Plus :
As much a privacy concern as a security issue, online ads range from intrusive to risk-inducing. The AdBlock Chrome extension blocks most of them, especially those than use Flash, prior to downloading
Secure Profile :
It's all fine and good not to share your passwords or browsing data with unknown online parties, but what about the people who use your PC? The Secure Profile Chrome extension encrypts and password-protects your Chrome profile data -- including all those stored passwords and form auto-completes.
BugMeNot Lite:
Almost every web site seems to want you to create an account and to track your access history across the Internet even if you only plan on visiting once. With the BugMeNot Lite Chrome extension, simply click CTRL+i and those onerous login forms will be auto-completed with anonymous information.
Password Fail
The PasswordFail Chrome extension warns you off any website that stores or sends your login password as clear text. Basically, if one of these sites is hacked, your undisguised password is sitting openly in a database, ready to be tried on all your other online accounts. PasswordFail lets you know if your password is an easier hacking target by calling out websites that don't encrypt their stored or e-mailed passwords.