I'm still quite fond of Firefox. I've played around with a handful of other browsers, namely Chrome, but none of them felt quite as right as Firefox.
I use Maxthon and have for years but I'm getting irritated now that every new version is introducing bugs...
Personally, I used to use Firefox 24/7, until it started messing with me. It became quite slow and all, I considered trying out new browsers. I first tried Safari, which I found extremely fast, but not that user-friendly. It also had a few bugs when it came to Facebook and blogging, so I let that go. I then continued on in my quest for a browser, landing across Opera, which I found horrible. I then found Google Chrome - my current browser. Definitely fast, secure for me, looks good, very simple and efficient. It's great if you're not looking for all that, just a simple browser that will do the job efficiently. If that's what you're looking for, Chrome is it.