Saturn V: yes, it got us to the moon, but it did so in an incredibly wasteful manner, throwing away nearly the entire rocket for every trip. For its purpose, just getting there, and getting there before the Soviets, it worked. America won the space race, the USSR lost and became history, the Cold War ended and the Iron Curtain was lifted, so arguably it was worth the cost for those particular circumstances. But as far as cost-effective repeatability goes, outside of the scenario of a Cold War, it's horrible.
Space shuttle: yes, it mostly works for getting things into space. That doesn't change that its original goal of cheap, reliable access to space went unmet. Rather than being designed to do one thing well, it's the result of a huge number of compromises, so instead of doing one thing well, it does everything with mediocrity. One estimate suggests the cost of the program, through early 2008, at $170 billion for a bit more than 100 flights -- over a billion a flight. That's not how humanity will ever truly be at home in space.
Other attempts since: X-30, canceled due to a more than tripling of expected costs. X-33, $1.2 billion down the drain before cancellation. X-34, nothing beyond a demo unit. Cost and time overruns every time, not to mention NASA always being a convenient political beanbag -- recall the current program only came into existence a handful of years ago.
Ultimately, as far as manned spaceflight goes, NASA does a great job at getting something done at huge expense when the need is critical. It does a poor job at cost-effective, routine manned spaceflight. It does a poor job at encouraging outside spaceflight development by private companies and such. Do you really think we can get into space en masse under NASA's guidance and initiative? One top-down organization held hostage by Congress and by congressmen looking for pork-barrel spending will not be successful at commoditizing spaceflight. Commercial spaceflight, of the kind being pioneered by the X Prize and the companies looking to fulfill demand that well outstrips what half a dozen flights a year can accommodate, is what what will take us into space again for good. I think the incompetent attempts by NASA play a part in reducing incentives for it to happen. Eliminating those will clear the field for truly motivated entities do do the work to make it happen -- I can't wait.