Now, what else does Apple do that requires a web browser? Besides WebObject, which I think we all agree is pretty irrelevant in this discussion, the only thing I can think of is the good old .Mac web services.
iTunes will be used to manage iPhones, that's pretty much obvious. But to manage your .Mac account — if Steve is indeed hinting of an upcoming major upgrade — does not make sense on the iTunes application. Here's where Safari comes in. One route that Apple can take, of course, is to bake a lot of the features into Safari and make available to both Mac and Windows customers.