Note about Firefox and IE, it all depends on your niche. If you are in a webmaster niche, more Chrome, FF... For me, IE is first, Firefox close second
You should never promote an inferior browser that holds back the web. Because of IE we can't use XHTML or SVG and more. In many cases, you can't even use javascript because IE handles the DOM poorly. IE holds back the web and its continued use makes you unable to see the its full potential. Do NOT use IE so we developers can present you with many wonderful things.
With my gaming blog it is about 70% Firefox. My other site is 60% IE. Gamers tend to be a bit more thoughtful with their browser choice.
I have 10 different websites, in 9 of them 90%+ of visitors use IE, and the only website that is 90%+ Firefox users is one that offers advice to novice webmasters. Others are based on topics like fashion, nutrition, education, senior living, etc.
I didn't expect such statistics, I check my analytics in every domain and the most used is Internet Explorer.