Generally speaking, Chrome, because it’s on my work computer and I don’t feel like bothering the tech guy to install anything else.
For mobile (iOS 8.something, iPhone 6) I use different browsers for different things. I use safari for quickly looking stuff up, iCabMobile for downloading files, Dolphin for streaming audio, and Mercury for reading long articles which require my full attention. I guess my favorite would have to iCabMobile; it has served me well for years.