It would be really nice to see a list of what those science benefits were, and when they happened. Every reference I have found, even from NASA, has only old accomplishments, like 30+ years old. Even NASA and pro-space scientists admit that experiments conducted in unmanned vessels are not only cheaper, but can be more productive. Some even argue that using manned vessels has seriously limited experiments best conducted in space. I find it remarkable that the accomplishments are not boldly published for all to easily find on the nasa.gov web site. As for the navigational techology, I don't see what value the shuttle may have had in developing or implementing it. The basic technology is sputnik era space science, augmented with good inventions that apply it well. The essence of GPS and similar technology is that it must be simple to deploy and maintain, othewise the system would be too fragile.
As for Hubble, why is it important? Sure, the pictures are pretty, but what value does it have? Do we really benefit much from observational astronomy? I'm pro-science, but astronomy has always seemed to be a hobby more than a practical venture. It's not like we can use space for much, given the distances involved. I always liked the influence of the likes of Keppler and Brahe because they helped advance our understanding of physics, but there doesn't seem to have been much of a payback from astronomy since then.
On the other hand, seeing a lot of the other NASA projects that aren't as "sexy", I'm impressed with what they are doing. There's a lot of very interesting and really valuable scientific work being done. We just hear about the boondoggles.