I use IE at work but I think the software is not reliable enough. I often have issues and lose the pages I am reading.
I used to rely on firefox a home but it has become slower and slowerlately, maybe because of the various add ons (which are cool though)
I now use google chrome. Efficient, fast, simple. I love the possibility to use the adress bar as the research field. And when chrome jumps, it automatically offers to find all your pages again, which is really cool.
Hope that helps