I alternate between Internet Explorer 7 (excellent simplified interface) and Opera 9 (fastest browser I've used). I've been using Mozilla Firefox since the 0.9.x days (I hated IE 6), and stopped using it when 1.5 came out - it just became slower for no reason at all, and Firefox 2 hasn't changed my opinion of it. Maybe Firefox 3.0 will be better, but for now, I'm with IE and Opera.