I say Google Chrome, or Chromium if you can't install Chrome with the .deb installer. Opera's a close 2nd (it has many features), & Firefox is last. Although I used to be an avid Firefox fan, their constant upgrading causes some of my favorite extensions not to work. I'm not one of those who refuses change, but it's ridiculous how FF upgrades so often. It's well documented, that FF is slipping in the ranks, on all OS's that it runs on.
What started me on Google, and I was once one of those who despised Google with a passion (privacy issues), was their totally, 100% Free phone calls in the US & Canada through their totally free email service. Being that I need to hold down my expenses as much as I can (I live on a disability check), this was really cool. I went on to discover Picasa, Google's photo suite, & really liked that. Finally, after much reluctance, I tried the Google Chrome browser. It's really fast!
Sure, you'll get some ads, but fortunately, there's an Adblock Plus just for Chrome. In fact, there's many extensions for the browser. I like the Panic Button & the Mini Maps apps. Everyone is different, I know, but I don't see how one can go wrong with Google Chrome (or Chromium). BTW, I really can't tell the difference from each other. One can import bookmarks, extensions & other settings, everything "just works" with both.
Proud Linux Mint user since 2009