xB Browser is a free open source Firefox based web browser that gives you secure, firewall bypassing browsing power on tap. The free version uses the Tor anonymous network, which is slower than conventional browsing but hides all your important bits safely. Worth a look.
It does not store a cache on the user hard drive, nor does it store cookies, so there is no mess to clean up with eraser programs. xB Browser also has advanced features such as SSL MD5 RSA certificate vulnerability detection, DOM object and flash cookie protection, cross-site scripting attack prevention, user-agent cloaking, and java proxy control. xB Browser also detects and disables malicious browser addons that are hidden in the windows registry.