Well that is a very hard one. As both this are true competitor of each other and have their own unique features. From both of this i would like to give and edge to Firefox as my favorite as i use it most.
Well if all you do is browsing and web research, I guess chrome has the edge. But when it comes to extended functionalities and web developer tools such as debugger and element inspectors, Firefox is the one to go for.
For eye candy lovers, safari has everything in the one visual candy aspect that it offers.