RP_Joe - 5:48 am on Apr 5, 2012 (gmt 0)
I think the meta description can help. If your number five in the SERPs and you have a good title, and a good meta-description, and people click on your link before others, this helps. I have seen evidence, that the position will change, because people click on the number five consistently. So by improving title tags and meta-description you can move up in the rankings. In order for the meta-description to work though, we are making assumption that you have optimized the title tag. This is often overlooked area.
Many people don't spend much time on the title tags. They do them once and forget them.
I don't think Google is paying any attention to the description. Google is paying attention to the users. And so if the users click on a link because the meta-description is better than the one above it, it shifts the ranking up.