Firefox is the best browser for work hands down. With the wealth of plugins available you can easily turn it into the powerhouse to perform your daily tasks, and it can also be used as your enternaiment center. The amount of flexibility it offers is amazing and it isn't matched by any other browser yet.
Yes this flexibility has it's downsides such as crashes, but the most common reason for that is some poorly manufactured plugin. You just need to figure it out which one is causing you trouble and disable it (it's easy, usually it's the most recent one :-))
AdBlock Plus and Element Hider Helper are the two most amazing pieces of browser software I ever used. With their help you can strip any site to basically bare and use only those functions you need. It helps a lot when you need to browse such cluster fucks of crappy "features" and ads as illegal tubes are to check if your stolen stuff is there. You guys probably wouldn't even recognize pornhub the way I see it in my FF
Opera is great too, I use it to check stats and read boards such as this one. Since they have added Adblock Plus a couple of months ago, I couldn't be any more happier with it