They're called browsers, not internet openers
Just a point if you search around for anything, you'll get far more luck by using the proper terminology!
Firefox is the most used by people who know what they're talking about and not without good reason. It's mature, secure, stable, fast and has a wealth of add ons and community support should you need to do something it doesn't support out of the box.
Chrome is great - but hasn't got the same amount of plugins out there that firefox has and is still fairly new out there. I have used it and it's very good - but I rely on a fair few firefox plugins so I'm sticking with that for the moment.
All in all, if you stick with firefox or chrome then you really can't go too wrong