My main browser and my default browser are two different things. I keep IE as my default browser, only use it for downloads, and have it excluded from my outbound rules on the firewall so that when it is opened, it is stopped by the firewall unless i allow "this adds additional security" ... My main browser right now is Comodo Dragon, i use it for everything but downloads..
I used to use Chrome most of the time, but it will not function right. It crashes, or is slower than Firefox for me, but it always crashes, so I use Firefox with Opera as a secondary browser.
I can't believe firefox is beating chrome in this thread, I used to love ff but chrome is way faster and more secure so for me it's chrome, secondary is IE9 but hardly use it.
I do have portable versions of firefox,opera,iron and maxthon but hardly ever use them.
I remain with Google Chrome as a main and IE 9 as the secondary browser. For what I need is more than enough. Only some sites I require IE to visit and most games forums and wikis are bookmarked on Chrome. The good thing about Chrome as opposed to IE for me is not the availability of many plugins. Since I sometimes require checking specific sites away from my laptop, Chrome allows you to sync your bookmarks on the go.