My understanding from reading Scott Aaronson, is that his belief is that most algorithms will not have significant speedups as a quantum algorithm, and that the

My understanding from reading Scott Aaronson, is that his belief is that most algorithms will not have significant speedups as a quantum algorithm, and that the currently known algorithms with large (exponential) speedups aren't very useful in the sense that they're just breaking cryptographic problems which were used solely because they were hard to break. In other words, don't expect everything to have a Shor's algorithm analogue.