It’s important to have meta tags for both your description and keywords. I figure it’d be like trying to scuba dive without a tank. Not really going to get that far.
However, it’s probably just as important to make sure the keywords and description reflect the content of each individual page. Of course, you hit up your main keywords and all that on your front page, as that’s what’s going to be indexed first. But it might actually count against you if you just copy and paste the same description tag for every single page.
It takes a little bit of time – but going into each page and making sure they’re just right can be well worth it.