What used to be known as Netscape was re-written from the ground up, and it forked into 2 projects. AOL bought part of it, and called it Netscape 7.1. The basic engine (the part of the browser that you don't see, but actually does all the work) is called the Mozilla engine. A group of Open Source Developers decided to make a product using the Mozilla Engine, and a completely open-source code-base (open source = anyone can see the code that makes up the program, and modify if they like) to come up with a new browser. This is called Firefox, and is the browser I use all the time.
I've found that Firefox is now at the point where it is possible to use it completely, and never use IE any more. Pages display correctly, and the browser is reliable and crash free.