The Department of Homeland Security issued a "Don't use IE" warning late in April. Microsoft issued security updates on May 1st. These updates can still be installed on Windows XP and IE. Although Microsoft has disavowed support, clearly some issues will still get attention.
Chrome was my choice for a long time and it is still neck and neck with Firefox. One benchmark gives the edge to Firefox with IE left in the dust (http://www.tomshardware.com/reviews/chrome-27-firefox-21-opera-next,353…). Firefox gets the nod on security. Google works because they know so much about you (but that is a story in itself).
Firefox has one highly seductive feature. All browsers get slower with use. Help > Troubleshooting Information > Reset Firefox is amazing. Speed resumes in seconds with hardly any interruption.
In Chrome, > Settings > Show advanced settings > Reset browser settings > Reset