The purpose of education is to prepare students to be productive citizens. This means get jobs, pay taxes, act as consumers and vote in elections. Education also teaches social skills. People have to learn how to work together, and coexist peacefully. This is largely what schools teach.
The main aim of K-12 education should be to give students the skills and knowledge they need to succeed in life.
I think that American education has gotten away from this to some extent. I think that we put too much emphasis on getting students to become "lifelong learners" and to love education for its own sake. This is a good thing, but I think it is a luxury when the US is falling behind in the quality of education given to its students.
I want my children to love education. But more than that I want them to be able to get good jobs and have decent lives when they grow up. I think that should be the main aim of our educational system -- to give people the skills and knowledge needed to compete economically. It's not noble and it's not nice, but I think that it is necessary in today's world.
The answer to this will vary and people will have divergent thought on the topic. I do think that if you are surveying where education is right now, the presence of standards based educational reform and high stakes assessment are an indispensable part of where America's aims in education are right now. Part of the reality of the No Child Left Behind legislation is to ensure that a discussion of the aims of or in education does not stray far from success on standardized assessment. When teachers discuss what aims in education should be or what the purpose of education should be, it is difficult to envision how a discussion of this does not involve, on some level, the pragmatic reality of standards based assessment that drives each school, teacher, and classroom. In the end, I think that some discussion has to be devoted to how standards and high stakes testing helps to provide aims or direction in education. At some point, perhaps there can be a discussion of how destructive this has become to the process of teaching and learning, but its presence is undeniable and has to be incorporated into such a discourse.