As a rule, never duplicate content at any part of your website where ever possible (of course unless relevant)! And keep it relevant to the page. don't confuse Google by using irrelevant meta tags and remember, the tags should describe the page, not give just a general overview in the site.
IMO, meta tags are helping now - they used to be key, then were ignored and recently I'm seeing the value of them increase. Some will disagree, to those I say Google something! Type in brown shoes into Google and see what ratio use meta tags to those which don't! Don't get me wrong, until 6 months ago, I didn't use them either, but my goodness I wouldn't do a site now without.
With bigger sites, I stuck the meta tags into the database (depends on your structure of course) which saved me time. However, if ranking high is important, I would suggest finding the time for this.