I love Firefox! can´t wait to see 2.0 So many nice plugins, and secure browsing. For using Firefox with adsense, the "adblock" and "adsense notifier" plugins are a must have. I dont use the google toolbar myself, but i like the quick search field at the top right. I use the Noia 2.0 theme, and have RSS imbedded as live bookmarks. Unfortunately Firefox often "time out" when loading... But that can be fixed. That´s about the only bad thing i can think of. I cannot browse the www without firefox! What browser are you using? Let us other DP´ers know why we should change browser...
I use firefox for web development, but that's just because internet explorer doesn't like to follow standards and requires constant work arounds to display anything properly.