Firefox seems to be the most popular browser around. My personal experience with Firefox has been great, its easy to adapt, its quick, has tabbed browsing and lots of useful extensions.
Below is the comparision chart from google trends.
ie 
opera 
firefox 
mozilla 
safari
goldcoaster said
this trend just shows that Firefox users need to search more often than other users thats all.
http://goldcoaster.wordpress.com/
goldcoaster said
Sorry, I was wrong.
This chart is showing search results, meaning more people need to search for help about Firefox than other browsers.
http://goldcoaster.wordpress.com/