There really is no need to use the much-abused "keywords meta tag" any more, as the SEO Theory and Analysis blog explains in Ding Dong! The Keywords Meta Tag is Finally Dead!. The main search engines long ago became able to work out for themselves what the key terms on a web page were, and didn't need to be told by a tag written by the website owner. So if anyone tells you that your website needs better keywords meta tags, you can politely tell them no thanks.
And if you have no idea what a keywords meta tag is, perhaps you need to put aside a tiny amount of your 2011 marketing budget and join all of us on the Insider Programme. Just because this tag is dead, doesn't mean the others aren't as important as ever.