Chromium & Chrome at home. Chromium for everything except blocking Google cookies. Google for Gmail and YouTube, except allowing only Google cookies. (Don't ask, I'm paranoid, which is probably pointless since I use all kind of Google services and an Android phone. It gives me the illusion.)
At work is Firefox for goofing off (because closing it = delete all history and cookies) and Chrome for... actual works.
Maybe when Firefox come out with the new Quantum engine I will go back to using it full time, but right now loading webpages on Gecko are too slow compared to Webkit, I miss the
Cookie Monster extension for Firefox, that's probably the killer feature of the browser for me (and the about:config). Also Firefox have all the extensions to download videos that Chromium/Chrome lacks or not as good.
I uninstalled Opera after they get bought by the Chinese (yes I know US govt spy too).