I use and love Firefox, but I don't think it's really fair to say Chrome is the new IE. The biggest reason why IE was a nightmare was because they were slow to implement new things, and had weird unpredictable behavior and bugs that only showed up in IE. You also had to have Windows in order to test with it. On top of that, crappy or nonexistent dev tools. Also (not their fault, but) many company IT policies required use of IE. Installing Firefox or Chrome made you a rebel ;-)
Chrome is far from perfect but they implement things fast and have great dev tools. If anything, I feel like Safari is the new IE. You have to have a Mac to test it, it's slow to adopt new features (sometimes aggravatingly slow), and it breaks in weird ways that Chrome and Firefox don't. I can't speak to the dev tools in Safari but I'd love to hear from someone how those compare to Chrome.