Before the 4 to 5 years in SEO, Meta tag is the important On page factor. But as google says now a days Meta tags are not so important. Keywords meta tags is optional. But meta description tag is somehow important. So Meta tags are not more important. Concentrate other on page factors like title tag, keyword density and content. In SEO, Content is the King & Backlinks are the Queen. So just concentrate on other important factors, not on Meta tags.
The most important tags for SEO that you can include in your XHTML are the <title> and <meta name="description"> tags. However, using these two tags will not necessarily make a difference in increasing your site's visibility on a search engines listings. What Patel said, in today's search engine ranking depends on content & backlink.
Meta tags are essential. It is the only thing which symbolizes your website in search engine's view. It can never be ignored. Crawler reads at first your meta tags not content and backlinks. They are secondary things. Title and description inserted accurately is the key to high ranks. Keywords meta tag is optional, but only a foolish webmaster will ignore it.
Like they say Meta Tags aren't as important as they once were but in tight competition they sure don't hurt every little bit helps. The most important are the title tags and the Meta Description . Search engines usually use what is placed in the meta description as what shows in your search engine results. So it is a good idea to have something very descriptive, relevant and along the line of a call to action to help add to the possibility that searchers click on your link when they see it, my thoughts anyway.