We would add this: why aren't you already using multiple browsers? They're FREE! Heck, download them all, collect them with your friends, and configure them for particular tasks! We routinely use three browsers during our workday. One is limited to our Intra and is all but crippled for Internet use. And the others have a variety of plugin configurations and privacy settings.
If you (and your organization) are still using just ONE browser — just what are you waiting for? A budget?