One browser can't rule them all
Nothing good can come out of having a single winner in a browser war. The last time a single browser won, it was IE6 and we all know how things turned out.
I believe that there are even benefits in using different browsers. I personally use 3 different browsers everyday. While I mostly use IE7 for testing applications, I actively use Firefox and Google Chrome for my personal browsing. Each browser implements a few things differently and I use each browser for different purposes.
Firefox is my most used browser, I use it for almost everything, its huge extension library is very important and gives it the edge for now (for me). As for Chrome, I use it mostly for running Web applications like FogBugz, Gmail and a few others in their distinct window. It blurs the line between a Web app and a desktop application like never before. I also like how Google is innovating with the browser and forcing every other browser makers to do their best. The launch speed and lightning fast execution of scripts really helps to set it apart.
Every war makes casualties and this one is no exception. Some losses are good, some are not. The plethora of browsers means one things for Web developers: headaches. As long as non-standard compliant browsers exist and are being used by people, developers will have to try their best to support them as much as possible. Fortunately, support for standards is improving with each major release which slowly brings us closer and closer to the death of IE6.
The browser war is a good thing for users and developers, I hope each browser will keep innovating and distinguishing themselves from the pack because one browser is not enough.