We’ve always recommended taking the time to write good description meta tags for all of your web pages. They may not influence your ranking in the search engine results, but if they’re used in the results (as what Google calls ‘snippets’), they’re the “call to action” which actually gets people clicking on the result. I’ve seen instances of a second- or third-placed result getting a higher click-through rate than the top one, because the ‘snippet’ is so much more attractive.
Now, your description meta tag might not be used as the search result ‘snippet’. But it might, especially if it contains the search term being used, and that should be good enough to make it worth a bit of love.
Traditionally, Google hasn’t given away much information about how its system creates ‘snippets’, but it recently published a short blog post on the subject. There’s also a section called “Create good meta descriptions” in the Google Help Centre here. Both articles are worth a brief read. I’d also recommend getting a ‘crawl’ of your site with the titles and descriptions listed for every page.