As per Google they wanted to build a new browser from scratch, designed specifically to be used with all the new generation of Web applications. Google designed Chrome to be more stable than other browsers, chrome is designed to be faster than the competition, particularly in JavaScript performance. Google designed Chrome to be multithreaded.
Google's browser is based on the WebKit rendering engine that underlies Safari. It runs only on Windows for now. Mac and Linux versions are in development.
To fight malware and phishing attempts, Chrome is constantly downloading lists of harmful sites. Google also promises that whatever runs in a tab is sandboxed so that it won’t affect your machine and can be safely closed. The browser has an address bar with auto-completion features. Called ’omnibox’, Google says it offers search suggestions, top pages you’ve visited, pages you didn’t visit but which are popular and more.
Here is a quick video of 10 Features of Google Chrome
Here's another video on the official Google Chrome announcement dated September 2nd 2008.