Although there are some web browsers which are in competition but there are some which are not in competition but they have some particular features which make them special for any particular purpose.
I use Mozilla Firefox, it is obviously the best browser and is faster than other browsers but when I use Facebook chat or Farmville, there is some problem of speed, and Firefox stops responding, so I tried different web browsers and found two browsers which are very good to use Facebook chat and Farmville. Those are
Flock is the award winning social web browser, it is friendly to social networking sites like Facebook, twitter and MySpace etc. It has a very good looking user interface and is easy to use. It is powered by Mozilla.
It can be downloaded from here.
CometBird is the second web browser which I found very good at Facebook applications. It is fast when I play Farmville game on Facebook.
You can download CometBird on the site.