I use Firefox. It's not as lightweight or fast as chrome but it has tons of customizable options and add ons.
I use IE 11 and Chrome, IE has improved a lot and works fine 90% of the time but I find it has issues with Youtube so will still use chrome for that.
Like everyone else, I started out with IE. Switched over to FireFox about 10 years ago (IE would never have stumbled upon tabbed browsing on their own). Tried out Opera for a little while. I like Safari but now use Chrome almost exclusively.
I was cruising around Redit and discovered Citrio. It's essentially Chrome, but it has a built in download manger/proxy switcher which is VITAL to my work. So, I use Citrio for work and Chrome for everything else.
Since I saw that Chrome is simple and fast enough I use it. But there are some minor differences between my old preference such as there is no possibility to watch a video file when you're downloading it.
I use Chrome on both desktop and mobile and as secondary browser in desktop I use Firefox, however by mistake I clicked on IE sometimes..lolz