I can't get that Bobby McFerrin song out of my head every time I see the Browse Happy logo.

The Web Standards Project (WaSP) has created a sub-site called Browse Happy - listing the reasons to switch from IE to another browser; and like the Apple ads - featuring profiles of "switchers". As a switcher myself I've been using Firefox for a while now and can enthusiastically recommend it over IE for both mac and pc (I use both). Try it - I bet you'll like it.