Some time ago I wrote about the importance of having a short and pertinent title tag (you can read it here).
The title tag might be the most important factor on the header of a site, but all the other meta tags (description, keywords and author) should also be considered. They will not make a huge impact on your search ranking but every little help should be used to fine tune your blog.
Meta Tag Analyzer is a very helpful tool for understanding your meta tags. All you need to do is to type the address of your site and it will report the status of the page, the number of keywords, the relevancy of the title, the quality of the tags and much more. Check it out.