To be honest: Firefox.

I use it every day since version 3. And a piece of software which has so much competitors and can withstand my urge to change is my winner

Agreed. I've been using it since it was called Phoenix. I switched to it from K-Meleon, if that's any indication.

@bahua never heard of both. I guess I'm too young :D

Chromium is sick btw.
And Project Spartan isn't that bad anymore either. - yet not open source I guess

@BambuSource

K-Meleon was like 2001/2002, though it looks like they're still maintaining it, which is cool.

Mozilla Phoenix was released in 2002, as a consumer-level alternative to the full Mozilla browser, which is now called SeaMonkey. I was 24. They called it Phoenix for a couple months before changing it to "Mozilla Firebird," and had to change that about a year later, to avoid name contention with an RDBMS of the same name. In 2004(I think), it was officially renamed "firefox," which my friends and I thought was really unusual-sounding. Now it's a household name.

I used to surf with it, but now switched to Opera, as Firefox lacks with implementing new WebStandards and JS Features

@bahua Now the name "Mozilla Thunderbird" makes a lot more sense...