What's shameful is the fact that NASA has received from the Government, in it's entire existence(50+ years), only a fraction of what was spent in the Iraq war alone in the last decade. But to put this into perspective, the shuttles were built on the promise that they would be cheaper per-flight than the "conventional" space-craft when in fact they ended up costing more. We'll only ride with Russia for a couple years before our own new "conventional" craft are put into operation.
Enterprise was a test shuttle that never went to space. It was never even equipped for space travel. Discovery was the shuttle that was in space for the longest amount of time, and flew the most important missions.