I think people are reading waaaaaay too much politics into the decisions to end the missions of the HST and the Shuttle. Try to look at this from a more practical standpoint.

The Hubble was launched in 1990. It has been producing amazing images that have not only advanced our understanding of the Universe, but have also given people within and outside of the field of astronomy a newfound appreciation of the beauty of the Universe. As was mentioned earlier, the next Hubble service mission wasn't supposed to take place until 2006. If the Hubble lasts until then, this will mean that its mission will have lasted sixteen years. I would call that quite a success, and a job well done.

The Shuttle has always been a problem for NASA. While in many ways it is a great success story, the Shuttle (and its tempermental, fickle, and financially bottomless maintenance requirements) is the single largest expense that NASA has, drawing funds that might be used for actually advancing spaceflight into just keeping us in orbit. What if the money being burned year after year on the Shuttle could be put toward developing new heavy lift rockets, or research for better propulsion systems? I have read that a single launch of the Shuttle costs in the neighborhood of 500 million US dollars. How many better ways could anyone on this board, let alone the people at NASA, think of that this money could be spent? Combine this information with the safety record of the Shuttle and the years that it has spent out of commission due to catastrophic failure (and subsequent analysis and retrofitting), and cancelling the Shuttle is an idea whose time has come.

To sum up: The Hubble has served its purpose, and the Shuttle is a money pit and a dead end for spaceflight. It's time to change NASA's focus and move on to other things.

EDIT: Fixed the number of years the Hubble would be in use if it lasted until 2006. I never was good at math...