Figure it like this, many years ago - all the search engines used meta info. Google decided that the info wasn't too trustworthy, seems some webmasters would actually lie about what the site was about !!!

go figure ..
Google is very ADVANCED compared to other search engines, but all the little guys and trying hard to catch up to Google. Whatever Google is doing today, the little guys will be doing eventually. So optimize for Google, and make it backwards compatible for everyone else and you should be good to go.
Google's advancement allows it to go more into the page to see what the content really is and is now to the point that their bots can not only read the words on the page, but can give weight to the words based on keyword density (like using the same word 3 times in 100 words is 3%) AND with the LSI, weight based on OTHER words on the pages. (LSI is a fancy way to figure out how the words are used in context. Lemon on a car site is way different than lemon on a cooking site.) (Oversimplifying LSI for demonstration)
But, there are tons of bots floating around from tons of indexing sites now. Some still use the meta's and still send traffic (albiet small amounts, but traffic is traffic). As technology grows, the middle level search engines will use the LSI technology more and more.
So, use the meta tags? YES. Traffic is traffic. Takes just a minute and might get some visitors eventually because of it. Use it to be backwards compatible if nothing else.
As stated above, good meta tags will make your site look nicer in results pages - so don't stuff them, make them readable and useful while including KEY keywords. It's a very short ad that you get for free to grab someone's attention.
Copy someone else's meta tags? Rewrite them a little if you do. Nothing wrong with getting a good idea and using it yourself - but you should be unique. Switch a couple words around and good to go. The ONLY problem with this is making sure the same meta tags actually pertain to your site. A quick tweak will make sure they do.
Lastly, grab a newer book on SEO for Google, lots available here in the forums. Google is constantly changing, and while they are not the ONLY game in town - they are the biggest for most people. A great way to learn about Google is to go to Google and ask them.
Code:
http://www.google.com/support/webmasters/
Too Soon