The safest way to surf the web is a two browser method. In my opinion there are two types of websites: semi-trusted and un-untrusted. Notice I failed to mention "trusted"; trusted websites don't exist. In this post I will explain how users should utilize different browsers when surfing the Internet.
The semi-trusted websites are sites such as corporate intranets, Google, and Gmail; just to name a few. These are the type of sites that have a remote chance of containing malicious attacks. With these semi-trusted sites, I am comfortable using browsers such as Safari and Internet Explorer.
Semi-trusted websites are the types that you use for work or personal use. Always remember that your credentials may be cached in your browser. This means the browser may contain username and passwords that if compromised, could result in the loss of personal or corporate information. In order to avoid this loss, I recommend that you do all other web surfing to un-trusted sites in Firefox.
The two browser method separates all potentially cached information in each browser. If NoScript fails to prevent an attack, I don't have any important credentials in my Firefox cache. This is not perfect, but it makes it harder for driveby attacks to compromise confidential information just by browsing the Internet.
One last tip:
Do not copy information such as credit cards to your clipboard, ie. Ctrl-C.
Attackers can easily grab this information from your browsers!!