The meta description's real value comes from its affect on the searcher

[mandy]

The meta description is an important element of your on-page SEO, yet its value is often underrated. Viewing everything in terms of search engine ranking impact blinds us to the opportunity that meta descriptions present search marketers. Admittedly, the meta description tag provides very little value in search ranking. Any value it may have once held in this regard has eroded due to keyword stuffing and other abuses by spammers intent on manipulating the search engines.

So how could this tag be so important if it plays so little a role in ranking? The meta description's real value comes from its affect on the searcher rather than the ranking. High rankings aren't worth much without the commensurate clickthrough. The meta description is often utilized by search engines as a basis for the descriptive snippet of text in the search result, to provide the searcher a summary and brief understanding of what the destination page is all about.

Thinking of it another way, the meta description is your opportunity to attract and compel the searcher to come to your Web site. Repeated keywords or meaningless text are not compelling reasons...

full article: http://news.com.com/8301-10784_3-9759378-7.html

[rose]

the meta description is your opportunity to attract and compel the searcher to come to your Web site. Repeated keywords or meaningless text are not compelling reasons...

Meaningless descriptions full of repeated keywords in search results are a reason not to visit a site.