The general consensus seems to be that posting daily is best, because this gives your readers new content to look forward to. If you have a pretty good following, your readers are likely to anticipate your daily posts and updating frequently will keep them coming back. One article I read compared blogs to newspapers - if the newspaper was going to repeat the same story every day, would you ever purchase a new one? No. The same is true with blogging - if you see the same post day after day, you're going to stop visiting the blog.
In the bigger picture, posting more frequently will give your blog better search engine optimization - meaning the each post is an entry point for possible readers to find your blog. The more entry points your blog has, the more like you are to attract new readers.
The answer to this question really comes down to the goals you set for your blog. If you are blogging for personal reasons it would be okay to post more like 2-3 times per week. However, if you are looking to grow your blog and attract a following of regular readers, it is important to update more frequently.
(Yes - this post was inspired because I didn't have time to post yesterday. I had a busy day at the beach and relaxing in the beautiful 80-degree Florida weather. It's okay to be jealous.)