I use all three actually. MSIE for my work's OWA, because I don't have a choice. (Unless IT enables pop on the server, boooo). Chrome for dailey use, because its quick and light. And firefox when I need use of some of it's many add ons. I mostly use it at home for Youtube, to kill those damn adds. At work though, Tabmix Plus and Colorful Tabs are a must for me.