There’s a nice short-article on W3C website titled Beyond Validation. It’s true that validation alone will not make a good weblog/website. But I see validation more as a structure of a building. And by making a valid one doesn’t mean that it cannot look good at the same time. There are many wonderful blogs that are also valid. Here is a nice quote from the article.

Validating one’s Web pages is growing to become the usual quality check. But a Valid page without quality content is a nice, clean shell, but nonetheless empty.Here are a few ideas and tools to help you with the other quality steps. Think content, think style, think navigation.