I have read a lot of online articles about browser security. How people can do scary things when you're not careful with your settings. And since I am not used to taking these kind of things with a pinch of salt, I take it seriously. Here is a simple method to stay on the secure side, and stay happy with chrome!
Go to Chrome Wrench(Spanner Button) > Preferences(of Settings). Go to The 'Under The Hood' tab. Click the 'Content Settings' button. Then click Block Sites from any Data, and 'Block all third-party Cookies without Exception'. And do not check clear all cookies when I close my browser. Now, when you try to sign in to a website and it won't sign in, there will be a little cookie icon in the right of the omni-bar. Click it. Then you will be able to tell chrome to allow the cookie.
All-though this Security Method sounds complicated, over time, Chrome won't get cluttered up. And you won't have to sign-in every time you open Chrome!